Ive been looking into all three myself. To sum it up from what I heared.
-BCNL aren't actually stealth because of the way it looks/noise/and the controls and water reserve being on the outside of the box.
-Sunlight has issues with light leaking between chambers but is easy to fix.
-Supercloset Trinity is by far the biggest with three chambers and I only heard one complaint from one person about it and his complaint wasnt valid as he regretted not getting a tent but most people don't have space for that and it defies the whole stealth part.
As far as building Ive been thinking and planning it and you save about a grand at best not including tools, labour, time trips to the store. But you gain valuable experience (experience cost money too, trial and error). I dont have the time or patience for that right now. As far as I can tell the box pays it self off after its first grow (Trinity yeilds at least a P a month according to posters). I dont have the time, patience or car for that matter at the moment. Me myself Im planing on a Trinity and expand with a self made tent after.