It can be worth investigating when you have access to meaningful fittings and a clear correction agreement. Our recommendation is to reject the purchase if its value depends on everything going perfectly the first time.

Compare three propositions separately:

Your situation Route to investigate first Evidence to require
You already have a flexible Vietnam itinerary An in-person pilot commission Confirmed appointments, cloth availability and time for corrections
You want several dependable business suits One pilot, followed by controlled repeat orders An accepted first garment and updated pattern records
You have persistent shoulder, posture or trouser-fit problems A cutter-led process with substantive fittings Relevant examples and an explanation of the proposed adjustments
You cannot travel A documented remote or US-supported process A fitting garment or another credible adjustment route, plus written remedies
You need a suit for an imminent event A domestic alternative you can inspect promptly Actual availability and a realistic alteration schedule

Do not compare Vietnam only with the most expensive US bespoke houses. For example, P. Johnson's US site advertises full-floating-canvas custom suits from $1,495, while Proper Cloth publishes alteration, remake and refund options. These are useful comparison points, not equivalent bespoke services or endorsements. (us.pjt.com)

Decision rule: obtain a Vietnamese quote and a realistic US alternative for the same intended use. Compare fitting access, delivered cash cost, time demands and remedies before deciding which is better value.