I wouldn't go for a hot rod series amp. they have a totally different character from what most people know as the signature Fender sound. For $600, you might be able to find a Super Reverb or a Twin Reverb. SInce Sonic Youth has two iconic guitarists, I'm not sure which side of it you're going for. But I don't associate their sound as much with tube overdrive as much as other bands - I would think you can get the sounds you're looking for using pedals in front of a Fender, and then you have that glorious fender clean tone with soupy silky reverb.
I have a Mesa Boogie Nomad 45. They sometimes go for $500-$600. It's got its own personality. Plenty loud - it has variable power amp wattage which is nice. Extremely flexible amp with 3 channels that each have different modes for fine-tuning what you're after. I think it's a ton of amp for the money. That being said, at times I've considered going for a Fender because I do find something indescribably appealing about the clean sound from Fender Reverb amps and I do a lot more clean playing than anything else these days.
I have a Mesa Boogie Nomad 45. They sometimes go for $500-$600. It's got its own personality. Plenty loud - it has variable power amp wattage which is nice. Extremely flexible amp with 3 channels that each have different modes for fine-tuning what you're after. I think it's a ton of amp for the money. That being said, at times I've considered going for a Fender because I do find something indescribably appealing about the clean sound from Fender Reverb amps and I do a lot more clean playing than anything else these days.