Julian,
Only having experience with Model Slipways kits (so far!) I would tend to 'lean' in their favor. They were very helpful/supportive during my build, and except for the usual, glue, paint, etc, their kits are very complete. I've only seen one other manufacturor with better instructions (and that particular company doesn't offer the same 'style' or detailing as MS does, not exactly the same 'class' of kit if that makes sense). Best advice I can think of is that if you like building, pick the kit that you like the best. Some lits require more 'nuilding' than others, but that's half the fun.
- 'Doc
PS - MS's helpfulness deserves some explanation. I'm not really 'happy' unless I can complain about something. That does not mean that whatever it is is actually a problem, in most cases it's because I decided to 'improve' something and end up in a mess. I didn't complain to MS, they contacted me to offer help and free parts! If that isn't exceptional, I don't know what is. I'm also 'blessed' with a conscience so didn't take them up on their offer (@#$$, it was my fault, not theirs!). All this certainly sounds like the advertising department and for that I'm sorry. I just can't get over their thoughtfulness.
PPS - After modifying this post several times, and still finding misspelled stuff, I ain't responcible for spelling!