So, the reviews are not completely wrong, but in my experience it is an incomplete analysis. When I do normal to deeper dives, I can read the computer just fine... Basically, if I'm below 35 ft or so, I'm usually ok. Where I have a difficult time reading it is on shallow shore dives. I just got my girlfriend into diving. She just got her OW cert, and we are doing a lot of shore diving at around 20ft in Lauderdale-by-the-Sea, FL. At that shallow of a dive, I've been having a hard time reading the computer. So, I'm looking to swap it for something a little bit easier to read at that depth, and I'm potentially going to use this opportunity to upgrade to a Perdix Ai. So, brand new, I would not recommend the VTX since the Perdix Ai is cheaper, and by all accounts, better. However, at this price point it will be tough to find a computer that beats the functionality that I have found with the VTX (including bluetooth sync with phone apps), and a very pretty display. It really just depends on your diving type.
I personally have had no issues with pairing my transmitter and receiver nor have I had any issues with the battery. In either case, the battery for both is user replaceable, and I always carry extras with me just in case, but have never needed to use my backups.
I hope you find this helpful.