we are a three person show and use cyrious sms
great program for complete job management and it is pricey, think we have about 2700 into it with two licenses, real crappy part is having tech support help you, they are usually fairly fast, but cost 120 per incident to help you, but we do not pay for the support on a on going basis as it costs more than a once a year call if that.
we use it on windows 7, had it on vista before and xp before and 98 before, it will work on older setups, they just will not support anything and force you to upgrade if there ever is an issue
great program we think, love the marketing aspect of it with the reminders that tell you if a client has gone so many days without ordering, keeps you on the ball for a follow up contact
i would also recommend graphixcalc, we used it for a little bit before cyrious, but needed a better solution for our shop