Well it sounds better than anything on the market at any price, it is immune from RF or EMI  interference ever making static noise or any other audio noise in your system and you can use it anywhere in the world without a license.

G50 does not yet have an official release date or price so I can't answer that one.

I have not used the G30 and have not even seen the G50. I do however have 2 XDR95 units. Years ago I bought the bets wireless I ever heard called the xwire. That company was bought out by another manufacturer but then some people inviolved in xwire started x2 and eventually were bought out by Line6. There is no better wireless at that pricepoint and I am not sure at any price point.

The only major downside with the x2 stuff is the crappy cable used to attach the xmitter to guitar. It is a 1/4 to mini cable and even though it "locks" it has been known to be iffy and generate noise if you do not treat the xmitter gingerly while playing.

The new G30 appears to use regular 1/4 sockets and should not have this problem.

Can you provide links to the G50 or G90 mentioned?

I am dying to replace my 2 x2s with whatever new product will do VDI over wireless or even if they did a seperate wireless just for midi over VDI. I would buy 2 immediately.