I'm totally new to this forum and haven't done any transfer printing at all. But I've been using Epson printers for several years with CIS, so I thought I'd offer my thoughts.
For about 3 years, I ran an R1800 with a CIS system I purchased from MediaStreet. The inks are pigment-based. Those systems are now offered by Ink2Image. I used the R1800 so much that I wore it out.
Without question, if you print more than 2 cartridges a week, go with a CIS. I must have saved 80% on ink by using the system.
However, you must print a lot or the nozzles will tend to clog. You'll then spend a fair bit of time doing nozzle checks and cleanings. That's quite annoying. With the system I use, I can get away without printing for up to a week, but that's really all. Since I print very regularly, that's not at all a problem. I have never had any problem with the ink in the tubes drying out.
I just bought myself an R1900. I ran through 2 sets of cartridges in nothing flat. I promptly installed my new CIS and am thrilled.
I can't speak to the quality of other systems, but there's no way I would print a lot without a CIS. The cost savings is huge with no loss in print quality.