I finally took the plunge and went for a system 4 and also got the spindle board (but thats for later). I justified the cost to myself with the good reports I read on here, and the help thats available from Roy. Also this will be OK when I move on to bigger and better things much later
I would agree that getting good drivers to start with is a good plan, and defiantly don't get bogged down with building some for a first machine (been there tried that). There is too much to do and just having smoother steeper drives really transformed my x-y table.
I got the 4.2amp with micro stepping from Gary(£115 for 3 i think) There also optically isolated so I didn't bother with a BOB. cut one plug of a printer lead and hard wired it :whistling:

Like Shaun I justified the cost as A; they can be used on the next machine or B; used on more than one if the same motors and settings are used.