My wife and I have riden our 400ex's for years on only trails. They are great trail bikes. I would recommend them to anyone.
I now also have a 700xx and it is amazing on the rutted terrain but it is a bit wide for the tight trails.
2008 Honda TRX 700XX - OMF Beadlocks, Kenda Kutters, CCP, ASV Levers, Houser Bounce Nerf Bars, ODI Rouge Lock-Ons, Pro Armor Skid, UNI Filter
2007 Honda TRX 400EX Red - Rath Racing Nerfs, CCP, Pro Taper SE Bars, ODI Rouge Lock-Ons, ASV Levers, GT Thunder 450R Shocks, Armadillo Swing Arm Skid, Pro Armor Skid, Alba Elite Bumper, Modquad Bar Clamp, 450R Rear Brakes YFZ450 Front Brakes, Kenda Kutters, UNI Filter