I would advise to be cautious, certainly, but I wouldn't necessarily advise against it.
I, personally, always prefer to have unlimited when I buy hosting with someone. Nevertheless, I like that unlimited to remain unlimited for me. Any limits should be the responsibility of the web host not me, the customer.
If they run out of space, it is their responsibility to purchase more space, not mine. And I don't want to have to pay extra for it if/when they do.
Apart from that I'm perfectly happy.
I do see your point, however.
I just prefer to have unlimited. Though it certainly carries risks. So my advice is don't necessarily refuse an unlimited hosting offer, but certainly be wary.
Do your research before hand. Or don't bother buying it.