Let me illustrate my current gaming circumstances and let that guide your decision if you will.
Basically we started a games club in December, Warhammer and 40K dominates, obviously enough (or not as the case may be, quite a few older clubs are now dominated by non-GW fantasy games as older players get grumpier and more anti-GW in outlook). When we first started there were no Warmaster players at the club at all, luckily though Space Hulk was newly out and I played a lot of Space Hulk, still haven't finished the campaign though.
Anwyay, there is now one other guy at the club that plays Warmaster, and now Warmaster Ancients (personally I find WMA a more satisfying game to actually play). However, in merely just playing Warmaster at the club, and talking about how great a system it is whenever possible, guys have dug out armies they've had sitting in blisters for years, are considering getting into the game and so on.
Obviously it goes both ways though, and you need to show willing to play their favourite games. And ultimately for me playing different games is a good thing, as it means playing different people and adapting to different styles of play and exercising my mind a little in trying to fit the different game systems into my head.
But, oddly enough I suspect that if anyone else at the club starts to dabble in historical Wargaming, as I and Rich are already playing Warmaster Ancients, I'd be very surprised if they didn't choose Warmaster Ancients over any other alternative systems.