As a now 1-year guitar player, this was the first amp I got and was exactly what I was looking for – a small, but practical and nice-sounding amp.
I am a student and living with my parents. They are not musical at all and thus wouldn't appreciate me playing in high volumes, especially as I am not yet very good at it. This amp is great for playing in lower volume, some other bedroom amps (1-5 watts) sound bad when not in full volume, this sounds great in any volume.
It also has quite a lot of practical features, such as the overdrive channel, EQ and delay levels. It allows to play around with the tone, giving a chance to experiment with various options. I find the delay control especially attractive.
The overdriven sound on this amp is excellent. As a huge rock fan, I'd say the amp produces a great rock guitar sound. I started to play guitar to learn some AC/DC songs, and I could get a pretty good Angus Young tone with this. The overdrive channel has a bit too much gain for my taste, but I have played some Metallica on that and it sounded fabulous.
For the negative part, it doesn't come with a power adapter, but you can get one for 15 euros on Thomann. I still sometimes use the same batteries it came with a year ago, so using batteries exclusively isn't that bad either.
Also, I seldomly notice a crackling sound when playing on high gain. It's not feedback, don't know what it is.
In summary, this Blackstar mini amp is a great one for beginners, can't imagine a better mini amp for this money.