"Which is better : Mach1s or FlySurfers?"
The only person who can answer this question is YOU! This is because the answer comes down to personal preference. Both kites are very good and well received, but at the same time they are very different both in construction and in riding style. Go with the one you like best.
I tend to agree with people saying that a mixed quiver is not a good idea, since every time you switch from one type to another you'll have to adjust your flying style and most people find this annoying. It is only reasonable to say that if you fly one type of kite only, then with time you'll get to know it better and be able to improve faster/easier. The only exception to this is perhaps when riding in very light winds. Here FlySurfers (or RamAirs in general) are performing better than LEI in my opinion, because they are lighter, faster, easier to water re-launch, slice better upwind, etc. Very big LEI are heavy/slow and almost impossible to water-relaunch, not to mention they are really HUGE are require a lot of pumping. etc (again, this is my personal opinion)
With regards to jumping, the general consensus is that RamAirs are a bit more 'tricky' to jump (as the timing / speed / edging has to more precise) but go higher, especially when used at their upper wind range.