The real question is how much data do you intend to use and what you intend to use it for.
i.e.
Downloading vs. Interactive .
Trust me 384 uncapped falls flat pretty fast in the Interactive area...you want to watch live-streamed TV or HD Youtube clips? Good luck on that 384 line...sure it is "uncapped", but you will be going "oh FFS, more buffering??!?" pretty soon.
So purely download media (videos,software,music) which you can schedule and "consume offline" then 384 uncapped is perfectly fine. But don't expect to push through even as little as 20GB of "streaming content" on a 384 uncapped solution. Yes your line CAN, but you the person having to wait for it behind the PC won't...
The catch with uncapped is, you pay a "fixed price" whether you use 1GB or 100GB.
The 2nd catch, on a 384 line you need to seriously schedule+plan your downloads EVERY DAY to ensure you get the most out of that fixed price. If you don't download large pieces of software for offline usage, then uncapped at such a slow speed simply becomes a bit of a waste...this is how the uncapped solutions make their money afterall

.
And i've went full circle with this, i got me 384 uncapped and i downloaded like a mofo, 24-7 "balls-to-the-walls" and got round about 60GB in a month (aparantly that is considered a realistic amount to get taking into consideration downtime/slowdowns/human factors). While all this was going down, i could not browse,stream or game, because the very same connection was too slow for alot of those activities AND i would need to pause all downloads to do anything else. The 2nd month, i realised i have so much offline content that i don't see a reason to "keep up" a constant download stream and suddenly i'm doing 20-30GB and still downloading alot of "crap" because i can. Yet i still could not view the latest and greatest trailers/clips/content in HD "live" without popping an artery from impatience

. I mean it's a totally different mindset to now have to "schedule a movie trailer download" vs. "just freaking watching it now".
So i think there's alot of "initial eagerness" when getting uncapped, but in my case it fizzles out quite quickly in favor of getting my content faster and "on demand" .