Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Polar - Vantage V3 | Xiaomi - Watch S4 |
|---|---|---|
| Peak brightness | 1000 nits | 2200 nits |
| Battery life | 168 h | 360 h |
| Weight | 57 g | 44 g |
| Display size | 1.39 " | 1.43 " |
| Cellular | false | true |
Between the Vantage V3 and Watch S4, the Vantage V3 comes out ahead in several specs, while the Watch S4 wins on peak brightness / battery life. Overall, the Vantage V3 scores 69.2 and the Watch S4 scores 76.3 on our Mars Score.
Which should you buy?
The Watch S4 edges ahead on the Mars Score (69.2 vs 76.3), but the 7.1-point gap is small enough that the right pick comes down to which spec advantages matter to you.
The Vantage V3 does not pull ahead on any single popular-comparison spec — its strengths sit in the spec-table groups rather than the headline advantages.
Pick the Watch S4 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. Its strongest claims are peak brightness, battery life, weight, among others. The single most decisive one: Peak brightness — 120.00% more. 2200 nits vs 1000 nits.
Both ship with comparable ecg, spo2, water resistance, so those specs do not separate the two — focus on the differences below.
Bottom line: the Watch S4 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Polar - Vantage V3 or Xiaomi - Watch S4?
Xiaomi - Watch S4 leads the current Mars Score by 7.1 points.The more useful decision is the trade-off behind that result: compare display size, battery life against the way you will actually use the product.
Choose Polar - Vantage V3 if…
Polar - Vantage V3 does not lead a decisive measured field here, so choose it for price, ecosystem, design, or availability when those matter more to you.
Choose Xiaomi - Watch S4 if…
Xiaomi - Watch S4 has the measurable edge on peak brightness nits, battery life h, weight g.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Polar - Vantage V3 wins
- No decisive advantages.
Why Xiaomi - Watch S4 wins
- ▲Peak brightness — 120.00% more. 2200 nits vs 1000 nits.
- ▲Battery life — 114.29% more. 360 h vs 168 h.
- ▲Weight — 13.00 g less. 44 vs 57.
- ▲Display size — 2.88% more. 1.43 " vs 1.39 ".
- ▲Has Cellular.
Spec comparison
Design
| Spec | Polar - Vantage V3 | Xiaomi - Watch S4 |
|---|---|---|
| Case size | 47 mm | 47 mm |
| Weight | 57 g | 44 glead |
| Case material | aluminum | stainless steel |
| Water resistanceⓘ | 5 ATM | 5 ATM |
Display
| Spec | Polar - Vantage V3 | Xiaomi - Watch S4 |
|---|---|---|
| Display size | 1.39 " | 1.43 "lead |
| Always-on display | true | true |
| Peak brightnessⓘ | 1000 nits | 2200 nitslead |
Health & Fitness
| Spec | Polar - Vantage V3 | Xiaomi - Watch S4 |
|---|---|---|
| ECG | true | true |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Polar - Vantage V3 | Xiaomi - Watch S4 |
|---|---|---|
| Battery lifeⓘ | 168 h | 360 hlead |
| GPS | true | true |
| Cellular | false | truelead |
| NFC | false | truelead |
| OS | Polar OSlead | HyperOS |
Frequently asked
Which has longer battery life, Vantage V3 or Watch S4?+
Watch S4 lasts 360 hours vs 168 hours.
Do Vantage V3 or Watch S4 support ECG?+
Both support ECG.
Which has cellular, Vantage V3 or Watch S4?+
Watch S4 offers a cellular variant; Vantage V3 is Wi-Fi only.