Someone (sorry I forget whom) setup
http://www.ratemylinode.com which graphs your IO token usage. The graphs on the rankings page are pretty small, but they do show that people rarely hit their IO token limit.
On my Linode 160 I run Apache with my blog and a quite busy PHP site (15,000 hits/day), my e-mail server w/ spam assassin, and a few other small things. The only time I hit the IO limit is when doing an 'emerge --sync' on Gentoo.
On ratemylinode you can also get an idea of uptimes - my host is on 80 days and counting.
For me the best feature of Linode (aside from the server itself) is the community, both on these forums and on IRC. The people here are consistently helpful, friendly, and very knowledgeable.