Bluetooth has been a serious a boon for Lego's Technic division. It gives them true freedom, to the point where the two sets going head to head here – set 42124, the Off-Road Buggy, and set 42099, the 4X4 X-treme Off-Roader – are fun and capable enough to make it into our guide to the best RC cars, as well as our list of the best Lego Technic sets. They're just fantastic fun.
The question is not whether you should pick these up, because they're well worth your money; it is not if either of these sets are awesome, because they both are. The real question is which one you should get.
The 4X4 X-treme Off-Roader is slightly more expensive than the Off-Road Buggy, but, as we'll find out, it might offer slightly better value overall. Let's put them head-to-head and find out which set of wheels is top of the track.
Lego Technic Off-Road Buggy vs Lego Technic 4X4 X-treme Off-Roader: Price
If money is an issue, the Off-Road Buggy is the absolute winner here. At an MSRP of £120/$130/AU$200 it is much more in the save-up-and-enjoy territory than the 4X4 X-treme Off-Roader, which comes in at a somewhat pricier £200/$250/AU$380.
They're both cheaper than the sum of their parts by some way. If you want play with Powered Up components without buying a kit, expect to have a far emptier pocket.
Note that they both come with some rare wheels, and some of the 4X4's cooler components, like its unique gearing, do make its price far more palatable for the Technic enthusiast market.
If you're looking for an RC car rather than a Lego set, though? Steer clear: even the cheapest RC car can outpace these, at perhaps a tenth of their price.
Lego Technic Off-Road Buggy vs Lego Technic 4X4 X-treme Off-Roader: Design
These fit into two distinct sectors of the RC world: the Off-Road Buggy is, well, an off-road buggy, built to be reasonably bouncy and able to tackle the odd mild obstacle while remaining fairly stiff, while the 4X4 X-treme Off-Roader falls more into the rock crawler category, with some serious front suspension which pivots to overcome larger bumps, and a low gear option which ups the torque when you need it.
In terms of looks we heavily favour the 4X4 X-treme Off-Roader here, given that the lurid colourful exterior of the Off-Road Buggy makes it look like there's been an explosion in the ’90s factory - and the former's easily-detachable top shell makes it quick to tinker with.
Lego Technic Off-Road Buggy vs Lego Technic 4X4 X-treme Off-Roader: Speed
Lego helpfully doesn't list the speed of either of these models, but we can tell you the following: neither is what we'd call fast, which is handy given the naturally limited range of their Bluetooth controllers. Forum posts by GPS-packing enthusiasts suggest the Off-Road Buggy can pull off somewhere in the region of 4-5km/h, which is disappointing. The 4X4 is somewhat slower even than that, given that its wheels are driven by compact planetary reduction gears, sacrificing speed for torque.
But it doesn't tell the whole story: these are both fast enough for kids to get started with, they have enough pace to pull off the odd stunt here and there (including wheelies on the 4X4 X-treme Off-Roader) and there's no reason you couldn't re-gear the design if you're a real Technic head. Speed really isn't the point, particularly given that even the most complex RC car kits don't match the flexibility on offer here.
Lego Technic Off-Road Buggy vs Lego Technic 4X4 X-treme Off-Roader: Control
Both of these cars are, as we've said, controlled via Bluetooth, with Lego's Connect+ app doing the honours, but the interfaces for each are slightly different. For the Off-Road Buggy you get what is essentially a joystick, with a single control dealing with speed and turning; some users have found this quite tricky to get to grips with, and it wouldn't be our preferred control scheme, but again it's the perfect option for kids just getting started with controlling RC cars.
The 4X4 X-treme Off-Roader has a more traditional 2-axis control scheme, though there's a secondary one-touch control scheme which places an images of the car on screen and allows you to tap and drag to move it around.
That's really just skimming the surface of what's in the Control+ app; there are achievements and challenges to overcome, and both models get an accurate tilt and yaw readout to see just what obstacles you're able to tackle – particularly handy in the 4X4, but cool in the Off-Road Buggy too.
Lego Technic Off-Road Buggy vs Lego Technic 4X4 X-treme Off-Roader: Pieces
In our guide to the best Lego Technic sets we call both of these a great value proposition, since they both include Lego Powered Up motors and smart hubs which, sold separately, would exceed the value of the sets; the Off-Road Buggy includes two motors, the X-Treme Off Roader three.
But the smart hubs are specific to the sets and locked to their specific Control+ layout, and cannot easily be repurposed for other uses. The sets also can't easily be added to, so that headlight mod you're dreaming of may be off the table.
You do get some very cool components here, though. The 4X4's planetary reduction gears, especially, are very neat, particularly if you intend to use them in other projects, and both sets include tyres not widely available elsewhere. The Off-Road Buggy has suspension front and back, which Lego says was a first for a Technic set.
In terms of the build, there's really no competition: the 4X4 contains 958 pieces, and the Off-Road Buggy far fewer at 374.
Lego Technic Off-Road Buggy vs Lego Technic 4X4 X-treme Off-Roader: Which is best?
If you have the money and the inclination to go slow and steady, we'd absolutely recommend spending on the Lego Technic 4X4 X-treme Off-Roader – there's probably a little more play value in seeing what terrain it can tackle than there is in the Off-Road Buggy, and it's a more rewarding build. But that is not, in any way, to knock the Off-Road Buggy: it's great fun, and a good-value set.