i have a contact i use for tailored cashmere suits. make sure you do the measurements precisely and often do them 3 times to be sure. im satisfied with the results but there is nothing like a true fitting in person with the tailor since they make recommendations on how it hangs on you and even ask questions regarding comfort and can observe your full motion and how the suit reacts to different movements. tailors traditionally offer 2-3 fittings and then make alterations. thats really the only difference IMO between online and in person. well that and you can strike up a better deal or see new fabrics not yet listed. i have several tailored shirts and nothing else fits like that, theyre wonderful and cheaper than store bought off the rack mid to upscale brands, even the fabric is thick and rich feeling. be certain you discuss the style you want as tailors often make clothing to their default style, by that i mean the way it tapers, the amount of buttons on the sleeve, where the cuff falls, where the trousers break, etc etc. things to consider you may not have thought about.
word of warning if you intend on buying ladies suits for a lady friend FORGET IT. for some reason womens clothing never turns out correctly fitting outside of in store fittings. its all those curves and hips and boobies ... plus theyre picky creatures.