I've used both Shopbots and CAMasters for 3-axis work and find them both to be good machines with outstanding support. I can talk about the Shopbot Indexer since I owned and ran one for a number of years. Note, since moving to California I've been without an indexer.
I worked on the initial indexer tutorial which is now hosted on Bill Shober's web site which shows my setup on some pages: ->Link
Here is a link to Shopbot's document for Indexer setup: ->Link
The documentation was good setting it up. Phone support was helpful -- though we just needed it to make sure we were doing the right thing.
I'd recommend that you make a custom command for Z-zeroing relative to the center of the tailstock. We set it up so you could zero the bit off the top of the tailstock and it calculated the Z zero to the center. That makes using multiple bits on the same job much easier.
The gadgets make Aspire very easy to use with an indexer.