The 3000 works well, but is slow - the 4000 or 4400 is better - especially if you using rollfeed paper. The feed motor for roll paper on the 3000 is weak and doesn't pull standard thickness rolls well, but it's a simple printer to repair and the heads are cheap.
The 1400 / 1410 also works really well, but if I were doing high volumes, I would stick to the 3000
The Epson 3000 I have was brand new and barely been used. I'm going to try and make this one work rather than invest in something else. So- what do I sublimate then? Where do you buy the ink? Will it affect the heads or whatever the ink comes out of? Originally Epson strongly suggested not using it but it seems to be working for you all.
Contact one of the sublimation supply companies and talk to them about the steps needed to start sublimation... There is one on this list that has good customer service and they might weigh into this thread.
Basically, you buy the inks and transfer paper then select from the thousands of items that can be sublimated. You will need a heat press for these items. That is why you need to go with a company that has good customer service rather than just buying from Ebay.
As far as the printheads on the Epson, they will clog if you don't use the printer for a lengthy period of time, but printheads will clog no matter what ink you use.
The Epson 3000 is a strong but old printer model. If you have one then I would say, go for it. Like any ink jet printer there are basic things you can do to keep them running good. Prior to my life here, I ran two 3000's for sublimation. Feel free to give me a call if you have any questions. I would be happy to answer any you may have.