well a new one would be nice but if you don't have a huge budget then used is the way to go
Too much equipment to write down...
they both have pros and cons.

new-you will have a warenty-newest technologys

used-cheaper-vintage vibe depending on how old

new- usualy cost more-new tech may have flaws

used-no warenty-condition-some parts scarce (univox example)

the list goes on and on.
buying something like a tube amp through ebay would be risky. it will get banged up pretty bad during shipping so chances are if its old it will need the tubes replaced when it gets here or something else could happen. its the chance you gotta take if you want some vintage i guess. also you dont get a chance to play through the amp on ebay like you would at a guitar store. i'd say get one from a store unless you have your heart set on a specific model that isn't available where you are locally.
I've done very well buying tube amps on ebay. It's not my first choice, but sometimes a deal pops up and I have to have it. Overall, I strongly prefer buying used. I've bought thru ebay, Craig's List, and pawn shops. I've gotten quality stuff at very good prices that way. Why pay $600 for a new Classic 30 when the market is flooded with mint, used Classic 30's for $400 and under (for example)? Makes no sense to me.
You Don't Need a halfstack.

You Don't Need 100W.

Quote by jj1565
i love you slats.