For the OP I've had an 8753a with a T/R test set for about 15+ years. It works well except for the CRT which in recent years started acting erratically. I replaced it with an LCD screen from Newscope about 18 months ago and it's behaved beautifully ever since. The electronics in these workhorses is superb. My only fault is that the internal battery/supercap failed before I even took delivery of it, and I've yet tomfigure out how to fix it. It just means I need to recal every time I switch it on, which is no big deal in my use cases as pretty much every time I switch it on it's for a different frequency range anyway.
I also have an Anritsu Sitemaster which is one port only (I think some are two port, not sure), so these are fine for antennas, but not for measuring filters etc. The one I have is again quite old, I bought it second hand about 12 years ago, it is a VNA but the built in display only gives you scalar return loss. You need to use the long-in-the-tooth software and a serial cable to see the Smith charts. It's battery powered so you can use it in the field, but the batterries, ISTR they're NiCds, or nickel metal hydride, are the weak link. Next time I get around to replacing them I'll put in eneloops.
On the bench, the 8753a is what gets used, out in the field it's the Anritsu.
Keep in mind that as well as needing a "proper" cal kit, you'll need to make up and validate your own test fixtures and cal kits if you're measuring on board integrated antennas. Plus, in the design itself, placing optional DNP micro RF connectors on top of in line zero ohm links (or ceramic caps) at one or two points will be a big help. Not a bit deal, but it's worth mentioning. I use these
http://www.mouser.co.uk/ProductDetail/Murata-Electronics/MM8030-2610RJ3/?qs=dnvuLCnOKpt0o1NKcCkttA%3D%3D