The Revell kit is the old Matchbox kit, and it's 1/76. It' nicely molded, cheap and you also get a scenic base, some figure and another tank in the same box. RPM has more details but is considerably harder to build, and the instructions can be a bit confuse if you don't know the subtle differences amongst different makes. I never seen a Hät kit, but I read an article that described it as the balance between the Revell simplecity and the RPM accuracy. However here at least they are more uncommon than hen's teeth!
I'd agree with Diego. The RPM is very fiddly - really the 1/35 scaled down to 1/72, so lots of tiny parts, especially in the track assembly. Even the bogey wheels are in 2 parts, and the glue almost melts them away unless you're very careful.
HäT say their FT is due for rerelease in their E21 quarter, along with the German wagon.
Detailing for the HäT is in this excellent article:
"Sometimes things that are not true are included in Wikipedia. While at first glance that may appear like a very great problem for Wikipedia, in reality is it not. In fact, it's a good thing." - Wikipedia.
After I tried to build the RPM one I fully agree with the other comments a very difficult build,so I would go with the Revell one using bits from the RPM one for extra detail. Expensive but you end up with a nice model.
The most complex is the RPM FT some kits suffer from very fragile brittle plastic others are tough and flexible, its complex and fiddly but if you like a challenge it makes up into a good model.. you can also get very detailed etch brass kits for super detailing if you really are a masochist...
for mass tanks I'd go with the Hät Ft a fair model that takes all of ten minutes to make, but will need some detailing the major fault with it is the inaccurate tracks..
Revell/matchbox a fair model with a very low turret so this needs replacing if you have an RPM FT you'll find a complete spare turret in that which combined makes a good simple model and will fit in very well with the other makes.
Hope this helps
Cheers
-- Edited by Ironsides on Saturday 3rd of December 2011 11:57:07 PM