From what i recall the spider amps are a load of garbage compared to their big brother flextones. The flextones have a lot more tweakabilty and will sit better if you play with a drummer as they have a better cutting midrange.
I'd have a look at peoples opinions of it on
www.harmony-central.com as the review database there is pretty expensive.
FWIW i used to have a flextone two (basically a POD with an amp and speaker) and couldn't fault it until i took it to band practice and it wouldn't cut thru at all.
The spider will be a hell of a lot more versatile than any tube amp at that price tho - and at low volume ;)
If you can spend a bit more then get a flextone 3. It would be night and day difference. And a lot more tweakable.
Are you more into clean tone or heavy distorted?