navaras are ace, but lots of niggly probs. nothing major just small issues. had mine about 2.5 years now, if it's near the end of warranty it's defo worth the extended warranty. paid for ours(800 quid for two years extra) then door locking system went, it should have cost 600 notes.
if you get a back cover (snugtop etc like shown in the pic above) don't expect it to be water tight though.
trafic are ace to, had mine about 4.5 years now and only small problems like bulbs gone and a small issue with the radio whilst under warranty, had a service last week and needed a new track rod end, but thats the only thing major(ish) for a 5 year old van (about £120)