We’ve all seen the advertising, is it true, what are they really like? I see they are offering a built hull now, there not a bad looking unit, good for someone who can fit out them selves but don’t have the time to build a complete rig

Must be a few out there now?
As with everything the resale value is probably abit low for most people to consider

That's why I'm building with glass and epoxy. As Rene Tolman said: I'm too smart to build with pure fibreglass, and not smart enough to build with Aluminium. 

If you're an aluminium fabricator by trade then go with a flat pack. If you reckon you know how to weld and haven't done it professionally then steer well clear. It's one thing to put yourself through a welding school, it's a whole lot different to do a competent job with aluminium. I'm not a welder but I work in heavy industry and appreciate the skills required. Heat affected zones, weld procedures, splatter, decent gear, good power supply, a good work area with lifting equipment & cradles, ventilation & access to testing & materials specialists are all important.  If you have access to that stuff and know what it all means then go for it. If you built a trailer back in the 80's with a stick welder you bought from Hammer Hardware and it turned out 'pretty good' and think you can learn the rest on You tube then forget it.