Your best bet would be to get someone from Sage, Exchequer, Pegasus and possibily Access Accounting to come out and give you a demo and a price.
From my experience they are all pretty similar, with only a few minor difference between them. All are very user friendly, and easy to use. If you see all of them in operation you may discover you prefer the look and feel of one more than the other.
Also one might be more suited to your type of company (i.e. have a particularly good stock module, with full tracability etc).
Apologies if I have left out other possible systems, but as Bonafide's current supplier is pushing them to Sage MMS, I took the assumption of a certain size of application and discounted the smaller applications such as Mind Your Own Business, etc