Category: Sporting 4x4s 
Price Range: No data available
Clever fuel-saving technology, "green" image, Lexus reliability and quality, refinement and high equipment levels, value for money, smooth and quiet ride.
Not quite as planet-saving as the hype suggests, not particularly roomy, vague electric steering and drive-by-wire controls, shallow boot, not as dynamic to drive as many rivals. It's also neither a proper off-roader nor a strong towing vehicle.
A step in the right direction when it comes to reducing fuel consumption and emissions from large SUVs, if not a revolution in environmentally-friendly motoring. A thoroughly pleasant vehicle to spend time in, but it's rather a case of style over substance as it's not a particularly versatile 4x4.
The hybrid system is easy to understand, helped by the wonderful animated diagrams on the large colour screen in the centre console which show where the power is coming from, where it's flowing to, the state of charge of the batteries and just about all the information you'd need to know. The only problem is that the diagrams are so absorbing, you have to remember to keep your eyes on the road... The screen also hosts the images from the rear-view cameras - a great aid when reversing such a large, unwieldy vehicle - and touch-screen controls for many of the auxillary systems such as sat nav (SE-L versions). The controls are all easy to find, the driving position is excellent and all-round visibility is good for this type of vehicle, despite thick rear pillars and curved rear end. The shift-to-drive-and-leave-it-there CVT gearbox has its lever in the traditional central position, and has a proper stick, rather than the Prius's funny dash-mounted widget, which makes it feel more conventional; no unnecessary sequential-shift buttons, sports modes or other complicated trickery here to confuse.
The RX 400h falls down, however, with its rather vague, non-linear electrically-assisted power steering; as in the GS, it doesn't inspire confidence under fast cornering, lacks feel, and is somewhat disconcerting when it weights up and then lightens according to speed. It's difficult to get a sense of placing it accurately on the bend, especially when the body roll kicks in, and the very road-biased tyres haven't got a great deal of grip, especially on the ultra-smooth surfaces where we tested this car. The brakes and drive-by-wire throttle are also slightly remote-feeling; you never quite lose the sensation that you're activating an electronic process rather than a mechanical, hydraulic one with predictable responses. The RX is not an involving drive, though as expected, it's pretty user-friendly and relaxing for simply cruising around in. It's just not as adept as, say, a BMW X5 or Volkswagen Touareg, or even the huge new Land Rover Discovery and Range Rover Sport, all much more driver-focussed (and much more capable off-road as well).
It's by no means slow: top speed is 124 mph (plenty quick enough for an SUV) and 0-60mph acceleration comes up in 7.6 seconds. One of the advantages of electric motors is that they supply lots of torque (pulling power) at lower speeds over a much wider peak range, so acceleration is swift and smooth, without power and torque peaking too soon or too late - it just keeps on going. The RX is a heavy vehicle, though, and the V6 engine has to work hard when it's the predominant power-supplier. It can get a little noisy under pressure, especially when it starts revving itself up (an automatic process to aid recharging of the batteries, which does not affect actual vehicle speed), though it does maintain the usual low Lexus noise levels the majority of the time, and is beautifully calm at motorway speeds.
Subjectively, whilst the performance on-road is more than adequate for normal driving it doesn't feel particularly strong, however, a feeling reflected in the low 2000kg maximum towing weight - even a Kia Sorento can tow 2800kg, with 3500kg usually expected in this class. And don't expect much by way of mountain-climbing, rock-hopping or mud-plugging ability, either; the part-time four-wheel drive system depends on the smaller rear electric motor (delivering the equivalent of just 66bhp) to drive the rear axle when needed, useful enough for a bit of extra grip but not sufficient for going too far off-tarmac. This puts the RX 400h firmly in the 'lifestyle' category of SUVs, though to be fair, Toyota points out that its LandCruiser is the real off-roader in its range (and this may well be offered with a hybrid drivetrain at a later date, though the company is yet to confirm this).
