I've had the P800 for just over a year, totally pleased with it.
I have the roll holder attachment too and have printed off a few panos, no issues at all.
A2 prints are great , its good to have the option to print A2 even if you don't do it all the time, I often do.
Easy to set up and use and the print quality on both Matte and gloss paper is excellent.
I bought a replacement ink kit from Fotospeed that uses refillable cartridges, I just installed them recently and they are fine, can't tell the difference from the Epson inks, don't know what longevity they have but that's not really of any concern to me.
The Epson inks are about £45 per 80ml cartridge where the Fotospeed inks cost £250 for a complete kit including 125ml bottles of ink, the individual bottles are £25 each (for 125ml) so much cheaper than the OEM ink. They also include a test pack of A3 paper with a variety of A3 paper for free.
I've used a variety of paper, Epson gloss, Matte and lustre and got excellent results, but I also used paper from Fotospeed gloss, matte and lustre and get excellent results there too, Fotospeed offer a free profiling service for any of their own papers .
Don't buy paper from Fotospeed though, it's actually cheaper to buy from
Online Paper you can buy the Fotospeed paper from them and still get the free profiling from Fotospeed.