so regarding the naysayers on Shearwater AI, the chief naysayer is the owner of the company who has indicated they aren't exploring it, so don't get your hopes up, it isn't going to happen. If you want AI in a badass computer, buy a SeaBear, they have wired AI on their HUD and the H3 is getting transmitters in a few months but is already built for it so it will just be a firmware update.
Now, to the original question. The biggest issue is the cost, second issue is which computers have AI capability. AI is nice, I would certainly not argue against it if it made sense, but it doesn't. Transmitters are big and bulky on the first stage, and the computers are stupid expensive for not a lot of versatility, that makes them a bad choice for technical diving. Reliability is not something I've heard any reasonable doubts against recently and seems to be something similar to GUE's argument against not trusting decompression computers. Sure they weren't as reliable or good 10-20yrs ago, but times have changed.
Price as I said is biggest factor for me. I can get a Petrel for $750, an SPG with hose for $100 and I have the best computer on the market with something that works and is reliable. Cheapest AI computer I found is the Mares Puck Air at $500, you save $350 and get AI, but you lose bluetooth dive logging *has an extra cost USB interface*, digital compass, decompression, mixed gas diving, use of AA batteries, and you go from a gorgeous screen to the casio watch style. That doesn't make sense. You can get the Oceanic Atom 3.1 which is the only AI computer I'd personally look at for $900, so same price as the Petrel+SPG, but you lose the screen, digital compass, and versatility of using with trimix/CCR *obviously not relevant for rec divers*, but that is the argument on the technical side. With the reliability currently I don't personally see the need for an SPG on backgas tanks, especially for recreational guys. Keep it in the save a dive kit, but if your transmitter fails, just start your ascent, not the end of the world.
Suunto Eon is ridiculous because it's $1900 with a single transmitter, so that's just insane, Seabear H3 will be around $1500 or so with a transmitter when that comes out, and at least that is a much nicer computer and cheaper than the Eon, but is still very expensive just to remove the SPG for recreational diving.
With sidemount you're bound to at least two SPG's, and if you run your SPG's up then there is no difficult in looking at them because they're right in front of you the whole time, and if you're diving properly you should be able to look at your depth and time and approximate to within a few hundred PSI how much gas you have left so you only need to look at your SPG a few times during the dive. For ocean dives I check it when I get to the bottom, about every 10 minutes after that, and right before I ascend. The convenience of AI is theoretical at best and if the pricing was reasonable then you wouldn't see as many arguments against it, but when you have to spend much more to save a bit of convenience the math just doesn't work out.
If the Seabear H3 was around $1000/$1100 with a transmitter, I think you'd see a lot of recommendations for that for the guys wanting a premium computer at the recreational level, but the hard fact is that when you are in for $750 for a Petrel, it just makes it real hard to recommend anything else.