I have seen too many people with issues due to size to recommend the type VII as a first submarine. anyone with hands larger than a small child will have problems stuffing things into the wtc, and it won't float at the waterline without a lot of fiddling.
on the other hand, there are a ton of build threads on, and upgrade kits available for the Skipjack. It is only 6" longer than the type VII, but has about 4x the volume. It is also a modern nuke sub with much less freeboard, so it doesn't need a large-ish ballast tank.
for anyone living in the UK, i agree with U-33. get the skipjack, and the R&R WTC, and you will be in the water very quickly.