Online MTM in general is a crapshoot. They always advertise some magical technology where they can transform a photo of you into clothing that fits, and it's not really a consistent way to do anything. It would be better to get measured in person, and if you want to shop online, find a maker who a. has a good return/remake policy and b. will take the measurements from your tailor. But your tailor (or whoever measures you) doesn't have experience with the nuances of the MTM company's system (or, rather, their factory's system), so things will get lost in translation, so be prepared to have your stuff remade.
Also, a lot of mtm brands are built around the novelty of a skintight fit. A skintight fit doesn't actually look good. Be careful falling for that.