Well I've taken the plunge, so we'll see. Got a 57 plate with 125k on nearly immaculate given the mileage
Only just seen your thread mate & wish I'd seen it earlier to aid your decision - 1st word of warning, mind those trees in the passenger rear blind spot and don't back into one within 24hrs of getting it like I did!!

The bumper and tailgate bend easily!!
On a serious note I've had my 05 X trail 3 years and I bought it with 60k on the clock & I think they are good motors. Now done 122k and in the last year I've needed to spend some serious money on it (including new turbo), with more to follow so I'm looking to get rid, although I've used it for the intended purpose of going off road, shooting out of it, carting stuff about and generally abusing it somewhat!! A few things to note that I've since found out.
The turbo's are prone to going around the 120k upwards mark, as mine did. Cost of repair around £800 for a 6 month warranty turbo - Over a grand for 12 month!
The timing chains are known to stretch and rattle as mine is doing now around 125k according to my mate who owns a garage. He had one and sold it with that mileage on and bought another younger model as he used it for towing and loves them. I don't want to think about what will happen if it snaps and I'm just hoping it lasts ok for another few months before I chop it in!!
The wheel bearings can be quite costly to replace as they are pressed units and are not the cheapest out there.
The alloys are made of monkey metal and corrode badly on the older models if you go off road like I do and can affect the bead of the tyres, causing them to go down and need constant pumping up!! Not a biggy, just annoying when it's cold and wet!!
Like all cars you may get a peach, or at 125k you may soon encounter some problems (hopefully not!!) and I know it's now too late, but I would have said go for a lower mileage one.
Now you've taken the plunge, my word of advice is ring the AA and get a quote for personal cover with the repair cover of a named car included. Mine costs £28 a month for me & the Mrs recovery in any car not owned by us including homestart, my 05 X Trail and my Mrs 08 Altea and they pay out up to £500 a time for 6 occurrances in a calendar year. So my turbo only cost me £300 and they paid out no quible for the difference as long as it's been serviced! They also went out to my Mrs when it wouldn't start, sorted it out, put a new battery on and it only cost me the £35 excess per claim.
Bit long winded but hope it helps,
Stratts