well i never ordered a suit from yao, but from what i saw the stuff was nice. there are pros and cons to using this service vs p johnson, but they balance each other out really. if youre comfortable with the fit and quality of p johnson, then you dont need to change.
if you'd like a bit more flexibility over the design, and perhaps access to different fabrics, then yao is worth considering.
whilst yao is full bespoke, youre not going to get a fitting unless you tie it in with a trip to hkg. and if you were doing that, you'd have a whole lot of other options to consider.
p johnson is a MTM business and youre constrained to what they can offer you in terms of design. if youre looking for something more, this might be an alternative