Canon 8300 - No Question
Do your research of coarse... but...
Cheaper to purchase than epson
Cheaper to run than epson(uses less ink for same output)
Yes but I did an audit of the ink use over the past year and 4 months and discovered that 2100 ml of ink was unaccounted for. Not sure if that's a fluke or not but I was more than a bit miffed about that.
More user serviceable parts (no waiting on a tech person)
Not really. Epson will sell you the heads. Aside from that they sell all the other consumables such as cutters, etc.
In terms of repair... AFTER the warranty expires Canon charges $1400 PER INCIDENT. Doesn't matter if they come out and find you had a setting wrong, $1400 bucks. Epson by comparison charges $175 for the initial visit and then $100 per hour. Most of the time Epson repairs are going to cost a lot less than Canon repairs. The extended warranties on the Epsons are also much more cost effective.
WAY more 3rd party media support handling.
MCT is nice... needs a bit of work interface wise but this is definitely a nice feature. A big pro on the Epson side though is the spindleless paper transport which is pretty slick.
Image quality is indeed fantastic on the x300 series but cost wise... initially it's cheaper but in the long run I think the total cost of ownership for the Epson will be less (the 700 ml ink tanks are a lot less $$$ as well).