The M900 are not the best, STX are better. But then you would loose the nice integrated look of m900 and it's excellent brake levers.
As a side
I don't like the m739 shifters, find them awkward and just feel wrong.
Not till the next style came out did they start to feel nice and easy.
The M738 (m008, can't remember what they feel like) are a much nicer shifter than the M900, but then you loose the m900 lever look again.
You know, some things are worth having poor shifters for.
Bitd when my m900 died far too quickly (front stopped working, rear threaded the barrel adjust threading)
I moved to srt500R gripshift and never looked back.
Still I have a few pairs in use and can repair them quite easily. But the one with an STX shifter bodge bolted on is just a nicer setup
I have XT thumbies running as 8 speed. Can't stand sti or gripshift. Thumbies last forever and work every time, not to mention they are becoming valuable.
Pics are always more fun - the original Rapid Fire Plus was always a bit ropey, 1994 brought in much better designs but stuck with STI. 1996 offerings have a better range.
the 'new' XT 738/9 was actually better than the outgoing XTR, but dont tell anyone I said that, I might get lynched.
20 year old M950 XTR looks as fresh today as it looked ultra modern back then. The crap finish lets it down as as cranks could be polished after one ride in the mud.
But, it gave us some of the best shifters available
I quite like 7 speed XT Rapidfire+ or 8 speed M900 XTR Rf+.
I have used a few sets now and never had a problem. If you pop the covers off every 6 months and give it a bath of GT85 they seem indestructible!
I've gone for a pair of XT st-738. Mainly because hunspecialized had a good set at a good price on the for sale section. I'll keep my eye out for a set of st-M900 and if some come up at a suitably low price I may get them as well to compare.
Both extra click. They're the same but different mounts. XT alloy, DX steel.
Never had issues with sti's. More issues with getting thumbies to work on 8 speed. I've just swapped back to sti's. M740'so.
Dx and xt thumbies are not the same. Besides the mentioned mounts they also differ on the inside. Dx has brass washers where the Xt has superfine bearings.
I have a few M900 STIs in the bikes I ride and after servicing them they work great. I like them. Some people dont like their feel, because they have a rather rough sounding klick. The XT STIs work as good as the XTRs, but have a softer, less abrupt sound and feel.
But I have to admit, I like the Xt thumbies more on 8speed setups.
I agree with LGF,I think one of the best groupsets they brought out was 738/9.I ran it on my downhill bike from 95 to 02 and it was faultless,I would have never ran XTR on that bike.