Planet X do a good deal and seem to be Bike people so customer care seems good to me.
Ive had a TT bike from them and a Kaffenback winter commute.
The Sram kit is very good. Ive got Force on one bike and Red on another. The shift levers are a fair bit lighter in weight over Shimano.
I would say Shimano is a lighter action though.
As for tools I wouldnt worry about that one. Cassette chains etc all cross over with tooling. GXP Bottom brackets are the same tool fit as Shimano etc. All the other stuff is Standard alan key stuff.
You can always mix and match like on the mtb in time.
I have a Shimano cassette, chain and front mech and chainset with a Sram rear mech and levers. Pretty much same on my MTB.
I too have always been a advocate of Shimano I did 12 yrs in the bike trade spannering etc and loved the fact that even there basic kids stuff just works!!! Period
Sram have come a long way and should not be ignored.
You could always try Shimano V Sram. A lot of LBS have a road bike set up on a Turbo and you could see what you get on with.
I think PX have a shop in London now so you could try one?
MC