There are a lot of boxes in here.
Bring water, pls.
I meet way too many guys who want their first proper suit and go down the MTM route. IMO it just isn't worth the effort, money or risk for any guy's first few suits unless you have a very hard to fit body. It's only worth venturing into PJ and maybe Rob's type thing once you know what you want after a year or two of wearing suits everyday, and only if you truly have a passion for men's clothing. Online MTM is just a mugs game, anyone who gets this right on the first time has fluked it. Just go to MJ Bale/Herringbone/Azzaro etc, find something that fits and alter it.
I'll not be wearing a suit every day for a long time, but I'd like a suit that fits well. Considering the price for MTM in store is, in many ways, not that much more than OTR in store (and also takes out the risk associated with an alterations tailor). It's a good fit. What's an MJ suit $550? Plus alterations? $650? $700? For $50 more I can have a set of measurements and level of choice that far surpasses that. I can also visit someone that is knowledgeable and experienced.
To expound, it's also no secret that many generation Y's/millenibugs prefer having a pretty strict direction of choice and options and prefer things 'just so', which factors into a young man's choice too.