Transits are work horses BUT be very careful with them. They are known to rust like hell! Not sure about newer models, but certainly up until the late 90's early 00's they still rusted like crazy!
VW transporters are good, look for ex-AA ones if you go down that route, usually you can get them bang cheap at auctions. Plenty of conversion options with them too, the T4 is a very popular choice.
I have seen bands go for years in LDV Convoy's too. Royal Mail use them and again can probably get an ex RM one at auction for pennies.
The good thing about ex AA / RAC / Royal Mail / Citylink etc is you know they've had a full service history as it's a legal requirement for fleet vans. They will have plenty of mileage on the clock, but as long as that service record says it's up-to-date they shouldn't give you too much hassle. The ex AA VW T4's can crop up with 140k on the clock, and they will happily take you up beyond 240k without too much grumbling, really reliable motors. Plus the 2.5 TDi version can keep pace with a lot of decently powered cars. ;) (They are also really mod-able to squeeze more power from them, if that's your kind of thing).