One of them (12 inch thousand dollar windows 7 tablet) will be out this month, after that they will be released April, May, and June. The later tablets look to be comparatively priced to the Playbook.
I didn't see any hardware specs on that link - anyone else have any links?
Unsurprisingly, the thousand dollar model is much more powerful than the playbook, but I'm not spending a grand on a tablet.
The Epad Transformer (basically a tablet that comes with a keyboard dock), priced $399 - $699, due out in April, has a Nvidia Tegra 2 dual-core CPU, dual cameras, 10.1 inch 1280*800 screen and 16 hours of battery life.
The Slider looks to be the same, but with a sliding keyboard instead of a detachable one. $499 - $799 price, due out in May.
Holy crap RIM, you'd better get that playbook out soon. We haven't even heard from HP or Motorola or a bunch of other players yet.