I built my bench about 6 months ago in the same style as a total newbie, though I think yours is looking better!
The hardest part of this build for me, and the least emphasised in Pauls videos and blogs is the fitting of the vice. Paul makes it all look very easy and simple, but I actually found it quite difficult, especially after how relatively simple the rest of the build had been with Pauls techniques.
Getting the holes drilled exactly square, making space to mount it with the apron getting in the way, and getting the vice dead square against the front of the bench was very tricky for me. When I first installed it, my vice was slightly out of square, only by 1mm or so, but it made a hell of a difference when it came to gripping things evenly in the vice.
I ended up fettling and messing with it for ages to get it right, and I'm still not entirely happy with how it has turned out.
So I would advise planning how you're going to do it, get or make a jig for drilling your holes dead straight. Measure everything twice. Consider the vice you have purchased, where the mounting holes are in relation to your apron, and where your rear face is going to sit. Do you have space to get it all in front of the apron? Do you need to make a recess for it to sit in etc. If you need to cut a recess (because of vice depth, mounting hole position, and apron thickness for example) that potentially needs to be dead flat and square to the rest of the apron front as well.
I'm sure the more experienced guys here would have no problem with this whatsoever, but I sure did as a beginner so thought I'd share.
Regards
Dave