I have followed the progress of the Epson printers for a long time, and from reading the comments here and elsewhere, it appears that the new Epson's are still plagued with the same problems as my 1990's 660.
Determining that fact from the posts on this forum probably isn't providing you with a very accurate picture. I sell and service Epson printers, (I can sell Canon as well, but in 2 years I've never had anyone come in and ask me about them), and have experience with a large number of users of which none have ever complained about excessive cleaning with current Epsons. We currently operate 2 11880's, a 7900, a 3880, and a 4900. All but the 3880 use auto nozzle checks and clean, and about once a week one of them will trigger a clean. The 3880 has had one clog is the 8 months we've had it running. One 11880 is over 4 years old and has only required one of it's 3 maintenance tanks to be replaced, guessing it has cleaned less than 30 times in the 4 years. The 4900 is now several months old, and has triggered a clean one time since I started using it.
Of course each user will see a different experience based on usage and humidity, but circumstances causing a current Epson to clean frequently will also lead to a head replacement on a Canon sooner as well - they aren't "better" at not clogging, they just have an nice system which makes it transparent to the user (which is certainly very nice).
Yes there are issues with some printers (I myself had one which had to be replaced from excessive cleaning) and part of the problem arises from a useful concept of auto nozzle detect/auto nozzle clean which makes clogs similarly transparent to the end user. In the beginning the printers were plagued with false nozzle clog triggering unnecessary cleans but I've found recent firmware changes have made it reliable in my case.
My point is to assume every epson printer out there has the problems of some of those that comment on this forum is quite misleading, as is basing on experiences with a 4000. Satisfied users rarely post comments, and despite what many think Epson still outsells Canon in this type of printer by a substantial number.
This isn't to knock Canon, the new x300 series output is terrific, it has the advantage of instant MK to PK switching, and they technology does keep the clogged nozzles out of your face. But to be honest, there is no way I have used several hundred dollars of ink keeping my 11880 running. And if your customers are delighted with the 4000 output, the Canon x100 series certainly beats that.