I have a 2012 Kawasaki T4, and I really think it boils down to personal preference. The pioneer looks better if you intend to do more work related stuff. The T4 does have a smaller bed, but it still tows 1500 pounds, and the bed doesn't go away when all 4 seats are in use. The T4 is more of a crossover- it isn't as sporty as a Rzr or Can Am, but isn't as utility as a ranger or big red. With 55HP, you can still go to the dunes or trail ride stock.
I looked at all brands for months before my purchase, and the high performance brands weren't as reliable as the Japanese brands, and only the T4 was a true 4 seater. We love the T4, and if you can find a leftover 12 or 13, then price won't be as big of an issue.
2x 2008 TRX90
2006 Kawasaki KX65
2005 TRX250TE Recon
2003 Kawasaki KDX50