I have an air integrated computer, an Oceanic VT4.1, and the last day I dove. it kept losing connection with the transmitter. It would recover after a few seconds though. Happened multiple times on both dives, but it had never done that before. The unit is only a few months old, so I doubt it's the battery in the transmitter. Although I guess it could be depending on how long it's been sitting in a warehouse/store shelf for...
Point being, I don't think they're reliable enough, or they will ever be reliable enough to make me not want to have an SPG, or at least a backup wireless setup. The only way I would ditch the SPG is if AI computers became inexpensive, then I would purchase one to have as both a backup computer and pressure gauge.