(from a woman who shops a LOT): mens shirt and pants sizes are fairly standard - thats a good thing for this business. As long as you collect ppl's sizes, most things should fit. I would also consider having a style-determinant upfront. Like: do you want to look like mark zuckerberg, larry ellison, or sergey brin for example if geeks are your target audience (if not, use celebs.) at least this will generally put the…
Our thought is that there's value-add in having a fashion-aware person pick out clothes for you - so in your H&M example, for someone like me simply knowing the brand isn't enough, I would appreciate someone picking out specific shirts or pants from H&M. I also typically only go shopping once a year, so not having to shop would be a big convenience.