I have Quilt Pro and have been using it since version 4--now up to 7. It has a PC version and a Mac version so you don't need an emulator program to run it on a Mac and it's a little cheaper than Electric Quilt.
Http://www.quiltpro.com
There are also some other programs they sell that will work with Quilt Pro much like the add-ons for Electric Quilt.
Quilt Pro isn't as popular as Electric Quilt so there aren't scads of users to trade patterns with but there is a yahoo group for it as well as a forum on the company web-site where you can connect with others and share blocks or patterns. They also have a free block of the day and a free quilt of the month.
The moderators on the company forum have been very responsive to any questions I've had over the years.