The Quick Verdict
Honestly? These two together is the setup. The S70 on your wrist for course strategy and the Z30 in your bag for pin-precise yardage. At $699 + $229, you're at $928 combined — not cheap, but these products genuinely don't compete. They solve different parts of the same problem. That said, if you're choosing just one: the S70 wins on versatility for most golfers. It does more, shows more, and works hands-free the entire round. The Z30 is a focused precision tool that assumes you already know the course.
What They Actually Do
The S70 is a full-featured GPS smartwatch — strap it on and it shows you the hole ahead, hazards, distances, and strategy before you even pull a club. The Z30 is a laser rangefinder — you point it at a target and it tells you exactly how far away that target is. Both are legal in tournament play with slope disabled, both are made by Garmin, and both live in the Garmin Golf ecosystem — which matters more than you'd think.
The Real Tradeoffs
Precision vs. the full picture
The Z30 gives you ±1 meter to whatever you point it at — the flagstick, a bunker lip, a tree you're trying to carry. The S70 gives you front/center/back of the green. For a par-3 where the pin is tucked short-left and the front of the green is 12 yards short of the back? The rangefinder tells you something the watch can't. But for everything leading up to that shot — the carry over the pond off the tee, the distance to where the fairway kicks right, the layup zone before the creek — the watch has information the rangefinder will never have because there's nothing to point it at.
Speed of use
Glance at wrist. That's the S70. The Z30 means fishing it out of your pocket or bag, raising it, finding the flag through the 6x optic, pressing the button, reading the number, putting it away. Neither is slow exactly, but on a busy Saturday with a group behind you, the watch wins on pace. The Z30's advantage is when you need precision and have a moment to use it — not when you're rushing to the ball.
What a GPS watch shows you that a rangefinder never will
Standing on a tee box you've never played — say, a 390-yard par 4 with a fairway that doglegs left and a bunker cluster at 240. The S70 shows you the whole hole: where the bunkers are, how far to carry the water hazard on the left, and where the fairway opens up. The Virtual Caddie factors in wind, elevation from the built-in barometer, and your actual swing history to suggest a club. The Z30 can't help here. There's nothing to aim it at until you're standing in the fairway.
What a rangefinder does that a GPS watch never will
You're 168 yards out, but the pin is hard against the back fringe and the green runs away from you. The S70 tells you front/center/back, and you'd estimate the pin is back. The Z30 tells you 174 to the flag, 161 to the front edge. That's the difference between a 7-iron and a 6-iron, and it's exact. For golfers who obsess over club selection on approach shots — which describes most people who'd buy a $699 watch — that number matters.
The Garmin ecosystem connection
Here's where same-brand really pays off. The Z30 has Range Relay — it can transmit the laser measurement directly to a compatible Garmin device. Whether that includes the S70 specifically isn't confirmed in the product data, but both devices live in the Garmin Golf app, which means your round data, stats, and shot tracking all go to the same place. You're not managing two separate platforms. The Z30's Find My Garmin feature also means you're less likely to leave a $229 device in a cart.
Cost of ownership
The S70 at $699 is the big number. Add the Garmin Golf membership ($99.99/yr) if you want green contours and enhanced maps — and at this price point, you probably do. Over three years, that's $999 in watch costs. The Z30 is $229, runs on a CR2 battery that lasts up to a year, and costs nothing ongoing. If budget is a real constraint, the Z30's cost structure is simpler. Combined with the S70, the subscription math still applies to the watch side.
Tournament legality
Both have slope disabled for tournament play. The S70 has a tournament mode. The Z30 has a tournament mode indicator light. You're covered with either.
Who Should Get Which
Get the S70 if you're a one-device golfer. You play different courses regularly, you want course strategy and not just a number, you like having shot tracking and strokes gained without carrying anything extra, or you want a watch you'll actually wear off the course. The S70 can function without the Z30. The Z30 cannot tell you whether to lay up.
Get the Z30 if precision on approach shots is your priority. You already know your home course layout cold, you want one reliable device that does its job and never needs charging, and you're comfortable figuring out course strategy the old-fashioned way. At $229, it's also the easier entry point if you're new to distance tech.
Get both if you're serious about course management. This is genuinely the setup that a lot of lower-handicap players run. Watch on the wrist for the hole view, layup distances, and hazard avoidance — rangefinder in the pocket for approach shots when the exact pin position matters. They're not redundant. They answer different questions.
The Bottom Line
The S70 does more — a lot more. But "more features" isn't always the answer, and the Z30's single job is the one that directly influences what club you pull on approach shots. If you can swing both, you probably should. If you're picking one, the S70 fits more of your round.
Get both. The S70 on your wrist, the Z30 in your pocket.