If you browse through the forums, you'll find some regular posters who post links to their sites.
You'll also probably run across a thread or two (or more) about performance. I haven't completely moved my sites here yet (I'm slow), but I've been very happy with the performance here.
My decision to join Linode over Slicehost was based on:
price (more bang for your buck)
community (Linode's community seems to be a bit higher on the geek scale)
They also have a presence in 4 data centers across the U.S. where Slicehost is in 2.
Slicehost is also now owned by a huge corporation, not just a big company, but a huge publicly traded company. Publicly traded companies are owned and driven by their stock-holders, not their customers.
This could improve Slicehost, or this could degrade Slicehost, or make it disappear and slowly swallowed up into some "new" Rackspace offering. In my industry, I've seen huge, international conglomerates buy up private companies for their name and product. Every single time this has happened, they've taken a quality product and turned it from a product that independent retailers would carry, ruined the product and moved into the mass market grocery stores. That right there was pretty much reason number 1 why I decided against Slicehost.
However, Slicehost does (currently) have better documentation for tutorials and such. Though it appears Linode is going to be working on that since they've just hired a new technical writer:
http://blog.linode.com/2009/06/16/linod ... new-hires/
With some of the hints dropped and the ways some of my questions have been answered by Linode staffers, it appears there are some great changes coming down the pipe.