They weren't great computers as such, but for quickly looking up things or surfing the web they where fine. My father in-law kept one on the coffee table until it the battery just died after ten years or so. It was just a quick way to look up stuff or check emails.

There aren't really any good replacement. Personally I want a keyboard, so out goes the iPad and phone, Neither are device I truly enjoy using anyway. Even the modern ultra books are to big and devices like the GPD are too expensive.

Technically it seems like it would be way more feasible to build some like the EEE form factor today, but the market might be to small.