The verdict, firstCyril Favre

Default to the Khaki Field Auto 38 if its 47mm lug-to-lug sits cleanly on your wrist and you want a watch you can restyle on any 20mm strap — choose the PRX 35 if that span runs long, or if the integrated bracelet look is the reason you wanted a mechanical watch at all.

On paper these two are nearly interchangeable as a first mechanical watch: Swiss- and American-designed automatics with 80-hour reserves, Nivachron antimagnetic balance springs, sapphire crystals, 100m water resistance, two-year warranties and only about $50 apart at US list price (Tissot's own site lists the PRX Powermatic 80 35mm, ref. T137.207.11.041.00, at $795; Hamilton's lists the Khaki Field Auto 38, ref. H70455133, at $845). Neither number decides anything — the decision is fit, wardrobe and what you actually want daily wear to feel like.

The two watches solve the same brief differently. The PRX's integrated case-and-bracelet is the whole design — Tissot's own configurator lists just three compatible straps for the 35mm, so buying it means buying that silhouette specifically. The Khaki Field ships on a steel bracelet but uses a standard 20mm lug width, so it opens onto the entire conventional strap market the moment you want a change. A 35mm PRX and a 38mm Hamilton are also not separated by diameter alone: Hamilton publishes a 47mm lug-to-lug for the Khaki Field, while Tissot publishes no equivalent figure for the PRX's integrated first links, so the real span has to be judged on the wrist rather than assumed from the case-size number.

Tissot · ~$840PRX Powermatic 80 35mm

HAMILTON · ~$890Khaki Field

The other case

The PRX is not simply the fussier, less practical choice. Its integrated case and bracelet are a deliberately finished object — no accessory shopping, no strap to eventually replace, just one design decision made once. It reads as a compact, polished piece of jewellery that happens to keep time, and it dresses smart-casual and office outfits more intentionally than a field watch's utilitarian dial ever will. For a buyer whose whole reason for wanting a mechanical watch was that integrated-bracelet look — not adaptability — the PRX's narrower strap ecosystem isn't a limitation, it's the point.

Where it is decided

4 arguments

Actual wrist fit, not diameter alone

A 35mm PRX and a 38mm Hamilton are not separated by diameter alone. Hamilton publishes a 47mm lug-to-lug for the Khaki Field Auto 38; Tissot publishes no equivalent figure for the PRX 35, so its integrated first links have to be judged on the actual wrist rather than assumed from the case size. If the Hamilton's lugs approach or overhang the flat top of your wrist, start with the PRX; if both sit cleanly, the decision should come down to design rather than an assumption that the smaller number must fit better.

Goes to

Tissot

35mm, no published lug-to-lug
38mm, 47mm lug-to-lug

Wardrobe range

The PRX looks more intentional with knitwear, an open-collar shirt and smart-casual office clothes, where its bracelet-led silhouette reads as deliberate rather than sporty. The Khaki Field is less conspicuous with denim, outdoor layers and everyday casual wear, where a utilitarian field-watch dial belongs. Buy the PRX if you want the watch to dress an outfit up; buy the Hamilton if you want it to blend into relaxed outfits. These are style judgments, not manufacturer specifications, so there is no objective winner here.

Goes to

Draw

Dressier, bracelet-led
Casual, utilitarian dial

Adaptability after purchase

Tissot specifies an interchangeable quick-release bracelet for the PRX and currently lists three compatible straps for the 35mm, including a grey synthetic strap at $60 — a real but narrow ecosystem. Hamilton specifies a standard 20mm lug width for the Khaki Field, which accepts the entire conventional strap market, official or third-party, with no proprietary interface. Buy the PRX for the bracelet it comes on, not on the assumption it will become a strap watch; buy the Hamilton if you expect your taste or wardrobe to change over time.

Goes to

HAMILTON

3 official straps listed
Standard 20mm, any strap

Daily mechanical ownership

Both are automatics with an 80-hour power reserve, a Nivachron antimagnetic balance spring, a sapphire crystal, 100m water resistance and a two-year warranty, sitting about $50 apart at US list ($795 vs $845). Nominal thickness is a wash too, at roughly 10.9mm and 11mm. A retailer listing for this exact steel-bracelet Khaki Field reference confirms a date function, resolving the ambiguity on Hamilton's own product copy — both watches display a date. Decide on dial readability, bracelet comfort and whether you'll enjoy wearing the same style daily; don't treat either 100m rating as permission to swim without checking the manufacturer's water-use guidance first.

Goes to

Draw

$795, ~10.9mm thick
$845, ~11mm thick

Who should buy which

Tissot PRX Powermatic 80 35mm

You already love the integrated case-and-bracelet silhouette and don't want to shop for straps
You dress mostly smart-casual and want the watch to look deliberately finished, not accessorised
You'd rather start with the smaller published case size while your wrist size is still uncertain
A narrower strap ecosystem doesn't bother you — you want one design decision made once

See the PRX Powermatic 80 35mm

HAMILTON Khaki Field

You want one watch that moves easily between casual, outdoor and everyday settings
You expect your taste or wardrobe to change and want the standard 20mm strap market open to you
You've checked that the 47mm lug-to-lug sits within the flat top of your wrist
You want a readable, utilitarian dial over a bracelet-led design statement

See the Khaki Field

Your personal verdict

Your wrist's lug-to-lug tolerance, how often you'd change straps, and whether you want the watch to dress up an outfit or disappear into one can change the answer.

Find which one fits you

Frequently asked

Is the PRX 35 automatically the better choice for a small wrist?

No. Its 35mm case makes it the sensible first try-on, but the integrated case and bracelet affect its apparent span in ways Tissot doesn't publish a figure for. Compare both watches from above on your own wrist; the Hamilton's confirmed 47mm lug-to-lug is the number to check for overhang.

Can I change straps on both watches?

Yes, but not with the same freedom. Tissot specifies an interchangeable quick-release bracelet and lists three compatible straps for the PRX 35 — use accessories confirmed compatible with that system. Hamilton's standard 20mm lug width accepts any conventional strap, official or third-party.

Which is easier to live with as a first automatic watch?

There is no spec-sheet winner: both are automatics with 80-hour reserves, Nivachron balance springs, sapphire crystals and 100m ratings, and only about $50 separates them at US list. The Hamilton is easier to restyle over time; the PRX is easier to recommend to someone who wants its bracelet-led look every single day.

Does the Hamilton Khaki Field Auto 38 have a date display like the PRX?

Yes. Hamilton's H-10 calibre is offered with or without a date depending on reference, and the official product page for H70455133 doesn't spell this out — but a retailer listing for this exact steel-bracelet reference confirms a date function, matching the PRX. Confirm on the specific watch in hand if this matters to you.

Is $50 a meaningful price difference between these two watches?

Not on its own. At $795 and $845 US list, both sit in the same entry-level Swiss-mechanical bracket with essentially matching movements, water resistance and warranty terms. Spend the difference on whichever fit and wardrobe role actually suits you, rather than treating the cheaper watch as the better value by default.