I don't know about the iAlert version, but I
the True Fit. I still have one that Evie (my 5 year old) uses in DH's truck. It's sitting out now, and I have been contemplating selling it, but it makes me sad.
I guess some things to know:
1. It has a continuous harness. Some people hate that, some don't care, and some love it. With the TF, I feel like it's a benefit because of the next issue/
2. The harness adjuster gets buried . It's down low. Not really an issue on the ARB version, because there's a cut-out, but it's still not super easy. Since the harness slides under the kiddo's bottom, though, I never felt the need to tighten and loosen every time.
3) the lock-offs can be a little annoying. IF you have seatbelts with a fold in them to keep the latch plate from falling down, it might be incompatible, or at least, you may have to fiddle with sliding the seat in the "Sweet spot" to get it out of the lock-off. The ones with buttons aren't bad because you can pop them off, or just slide the seat a tiny bit to get them out of the way.