Perhaps a little stringent?
I switched to the uncapped 4 mbit line as soon as it was available. Whilst the capped account's auto-topup feature works well (generally -- I've had one hiccup where I lost connectivity and had to reset my router), it starts adding up, even at Afrihost's good prices. Since bandwidth pricing is flat (ie, same price per-gig no matter how much you buy), it just made sense: there's a point at which the uncapped option becomes cheaper and less hassle than the capped option (of course).
Typically, I download about 20-40 gig in a month -- but I avoid starting Steam too often because I know what a hog it is. Since the introduction of uncapped accounts, I've just felt free to not have to particularly watch my usage -- it's been great. Youtube as much as I like -- even the really silly vids

. Try the betas. Check out other distros even if they didn't come on the DVD with my Linux mag.
The original 200GB mark was, I thought, quite fair. Even if throttling started at about 100 GB, I would consider that quite fair. The current regime is, in my opinion, a little too harsh -- I'll cross that first throttle point for sure and might venture into the second one, at which point, my wife, who doesn't know any better (nor does she need to) will probably start to complain that the internet is slow. And she'll complain to me -- which means that once again, I have to start watching usage to make sure that I'm not downloading too many linux distros or betas from Redmond -- or that I've left my vpn connection up: that can really start to eat bandwidth.
I sincerely hope that Afrihost reconsiders the numbers for the throttle tiers. I understand and support a FUP -- and abhor the people who have had to abuse the uncapped connection just because they could.
Think about it this way too: let's imagine that you download movies (hey, I just want to get this idea out to the people who do download movies and the like: the people who are obsessed with downloading the interwebs are downloading content like this -- I don't see how you get, say, 300GB of legal content in a month unless you
re-download a lot of large betas and linux distros), all day long. Let's imagine that you want HD rips as well, so you download movies of the size 1-5 GB, putting the average at 3GB per movie, all things being equal. If there was a 200GB limit, that means you can download about 60 movies per month and still have plenty bandwidth available for regular browsing.
60 movies. Let's think about that. First, let's imagine that the movie studios can actually produce that many watchable movies (yes, you can start with some old ones, but there comes a point at which you've "seen it all"). That means you have to watch 2 movies a day, every day, without fail. Personally, I don't have 3-4 hours of spare time available for that in a day -- I don't know about everyone else. And this is doing the guesstimate with HD movies. If you were downloading, say, TV shows or regular old DVD rips at about 800MB each, we'd be talking in the region of 6-12 (or perhaps even more!) hours of content A DAY.
If you
"need" to download that much media, you need a life (and probably a job).
Not to mention that I would love to know where this will eventually be put. Since it would be near-impossible to keep up with watching what you download, you'd have to store it somewhere (assuming you aren't an ****** who just downloads to delete almost immediately; or a pirate trying to make money by downloading and burning DVDs for sale at the local flea market). Personally, I have about 5 terabytes of storage at home. That's not an amazing amount -- but it's a reasonable amount, I think. And I think that most people probably have that or less -- so at some point, surely the heavy downloader needs to ask the question: "Where do I put all this stuff?". OK, you can burn mountains of DVDs -- again: did you actually consume the media you downloaded, or are you just downloading for nerd points?
Overall, I've been quite happy with Afrihost. The service has been great, the line is a huge step up from NeoFAIL. I'll see how it goes next month -- but I'm hoping that the throttling tiers will eventually be lifted to higher levels. I understand that they can never completely go away, as long as there are assclowns who insist on raping the interwebs -- but I do hope for kinder terms in the near future.