They're not too bad if you don't mind whiplash. I would never put one in a street truck.
no kidding. i rode in my buddies fully build dodge thats right around 800hp. WOT is great, anything else and its like you get rear ended every time.
The way a 48 drives is entirely in the builder and what they did to the valve body.
I've had a built trans for 6 years; the first two years were crap, I killed it every 6 months on the dot (no joke, 6 months between rebuilds it was dead). And that one's shifting was a little herky but I don't recall it driving badly.
This one (changed builders, Goerend FTW) has been completely flawless, nice firm shifts but not as hard as before, and driving is silky smooth, there's absolutely zero "whiplash" or "feeling like you get rear ended" to it.
The trans itself is dumb, everything is controlled by the valvebody (except lockup and overdrive) and that's both nice and not-so-nice; towing it leaves some to be desired (although I've not towed with this Goerend) but other than that, driving couldn't be simpler.
I think the Allison should/needs to learn after changing tunes, is that correct? It seems the Allison is sometimes too overbearing in it's control, the Dodge trans couldn't care less. Same basic trans design is from about 1962...