Roy,
Not heard of that AC issue affecting UK cars, nor any owners of RX's over the last year reporting it.
Please in future could you post a link to other websites instead of copying the material verbatim, you could get this site in trouble otherwise!
As to the original poster's comment:
There's not much horrendous that routinely goes wrong with the RX300 and even RX400h considering how old they are now commensurate with age and mileage - major issues tend to be the exception rather than the rule.
When looking for an RX, routine service documentation is a must to ensure major service items have been covered (cam belt & spark plugs etc), alloy wheels are notorious for looking scruffy and cost around £400 to refurb. SE-L (RX300 not RX400) models have air suspension which WILL wear out over years and miles, so evidence of a recent strut change or factoring in something to the purchase price and having that set aside would be prudent. The Sat Nav & Bluetooth (if fitted) is long in the tooth now also. Other than that driver's seat usually has evidence of wear due to the soft leather. Also auto-dimming wing mirror glass is expensive to replace (goes a gold colour visible in daylight when bad) still works but at night everything seems darker and is a hindrance parking).
Make sure everything fitted works and usual used car purchasing due diligence is applied.
You may have had the v6 3L 1MZ-FE engine in the past in a GS300 if you ever had one of those, so you may already know what a creamy smooth, refined engine it is, which would be a bonus for you when test driving.
Let us know how you get on, but reliability wise from similar aged comparable SUV's (X5, Volvo, Tourag, Cayenne, etc...) the Lexus knocks the spots off them!
Chris.