This Amp-series might be one of the more famous ones in the world, and the "status" that it has is understandable. I've it stationed in my bedroom beside my little "studio" corner and of course, it's a good looking amp and also a sort of decoration. The features may be limited but that's almost what to expect, if you're looking to buy an amp from the AC-series you know what you're searching for. As in my case i'm a huge U2 fan and that's is actually the main reason why i bought it.
Basically you have two options, either the Top Boost or the Normal channel.
I'll summarize it quickly from my point of view.
Top Boost - No additional pedal is needed to create a crunchy/overdrive sound.
Normal - Might need something between the guitar and amp to crunch it up a little...
A really good additional pedal to the Top Boost option is a simple Compressor pedal, my main order is basically: Guitar - Dyna comp - Delay - Vox Ac15. And for solos i usually add a Boss Sd1. It's quite simple when comparing to the tones you can get.
Then should you buy it? It depends...
1. Do you want to imitate specific bands, for example U2, Queen etc?
2. Do you have access to a place where you can really crank an amp to it's max?
3. Do you have a few different guitar pedals? (Probably yes..)
If you can tick these 3 then you might be the one to buy a Vox AC-15.
Now comes the 3 opposite questions..
1. Do you play at home, ex in an aparmtment/townhouse?
2. Do you have a really expensive guitar and almost no pedals?
3. Do you want a Vox AC-15 but with the Alnico blue speaker instead of the Greenback stock version?
If you can tick these 3 then might not be the one to buy a Vox AC-15..
I'm living in a house with neighbours in almost every direction and it's not very often when i can even crank it up to 50% without worrying about getting complains, i've solved this sort of by having compressor with relative low volume on. But i'm not fully satisfied with that solution.
Then as i said it's features are limited. Tremolo and Reverb is the only effects you can mod around with so i'd recommend having a few pedals just to spread the capabilities.
And the speaker... i underrated the Alnico blue speaker and planning on ordering it to get it replaced with the Greenback speaker. I'm not saying the Greenback is bad (which it isn't) but it's not the tones i'm searching for. So dig into the two options just to be sure you're choosing the right one.
Summarized it's a great amp and of course a really good option if the AC-30 is too big for you. I'm only 17 and i do not have all the money in the world but i still find this amp "cheap" compared to its capability. And especially to U2 fans wondering if it's any good for "U2" purposes - It doesn't requires more than this amp and ex a Korg SDD 3000 to give me shiver =)