Since I don't own one you should take this with a large 'grain of salt'. I've read the reviews and know of one person that has one. The reviews so far have sort of struck a 'center of the road' thingy, not exactly a confirmation in either direction, and they need some 'salt' added to keep things sort of even, you know? My only reason for not trying one of them is the cost, ro at least the prices I've seen (haven't shopped around).
Antenna analyzers are definitely a handy tool to have around (I've had one of those 'unmentionable' named one since they first came out).
The one person who has one that I know of seems to be happy with it. He has used one of those 'other brand' ones, so I figure it must be an improvement. The 'Rigexpert' analyzer isn't a 'lab-grade' instrument, it's in the same general classification as the MFJ-259. It really depends on how well the user understands what an analyzer can do and just how accurate the end result has to be.
So, after reading all that, I hope I didn't waste too much of your time.
- 'Doc
(Have I got a deal for you! If you get one and don't like it, I will give you 10% of the purchase price you gave for it, howz-zat for a deal, huh?? You pay shipping of course.)