I've used the 2400, which I believe the 2800 replaced, for a few years, and it has been good, but I recently passed it on to a friend and bought the 3800. The print quality seems identical, but the cost of ink is considerably cheaper with the 3800, and it will print up to 17". I found a refurbished 3800, with a one year warranty for about $300 over the value of the ink that came with it.
I have a 3800 and although large is very manageble and also will print on small paper as well as the very large sheets. The cost of each cartidge, although high ends up being much cheaper than my older 2400. Also, a critique of the older large format Epsons was that of nozzle drying out - I have NO such problem on the 3800 and can recommend it highly - even if upgraded I would be hard pressed to find a reason to switch.
This looks like the time to buy the 3800. If I'm understanding things correctly, the discounted price at B&H is $1,145 and then you add a $300 Epson rebate on top of that.