Made the switch to SRAM a few years back and in general have been pleased with the decision.

However, I am now in need of a new front mech and was shocked to find how much more SRAM ones are these days compared to Shimamo. Also the X9 is also quite specific, i.e. they are not dual pull or different clamp size adaptable.

However, most of the Shimano stuff appears to be both Top or Bottom Pull and 31.8&34.9

Seeing as you can run either SRAM or Shimano front mech with SRAM shifters I am erring towards going back to Shimano.

Any thoughts?

whichever is cheapest at your LBS 😉
in terms of functionality there's no difference; well no more than that between x-7 and x-9 or deore and xtr

SRAM; whilst it may not matter which you use, one brand throught still seems to work an awful lot better. You won't be fussed about the money when the shifting is perfectly effortless

I have XT on my SRAM shifter setup, works perfectly.

I prefer SRAM front mechs simply because they are built like tanks, and last forever. I was lucky and got an X-gen for £5 which has been on the bike nearly 3 years and has not the slightest sign of any play, unlike the Shimano ones I've had which always go wobbly within weeks. I just wish SRAM bulit their rear mechs as tough as their fronts!