Trek 6500 Disc or GT Avalanche Expert?

G'day all,

Am in the UK and have the opportunity to purchase either of the above at 60% their retail value - but got the opportunity to get either a Trek 6500 Disc or GT Avalanche Expert at 60% their retail price! Both seem ideally suited to what I want - have a very similar spec and the price difference is negligible.

So - without me going into great detail about what I'd use them for - would you please let me know what you think - and tell me any pros and cons of either bike (or brand)?

Thanks
Martin