Regardless how much you spend on you IP PBX, a poorly designed or equipped network can render it useless. Irritating for the home user, pure disaster if the survival of your business depends on it.
There is a large number of manufacturers around catering to every need and budget. Household names like Cisco, Linksys, D-link, Planet and others supply hardware of good to very good quality, it all comes down to price and preferences. And features, of course. You dont want to install a production PBX on a network shared with PC’s and printers, at least not if you are stuck with a switch that can not be monitored and configured in order to secure the need for QoS/ToS. In the forseable future I will do some testing of various equipment, and I am counting on you to point out things I overlook and forget, and of course when I make a total fool of myself.