These are a remarkably good amp for their price and size. As an amp for small gigs (or even for bigger events) these perform far beyond what they look like they should be capable of.
The first thing to note about these amps is obviously their size. They are significantly smaller than a loaf of bread, and look amusingly small on top of a 2x12 cabinet.
Having said this, the sound could never be described as 'small'. These are louder than any amp this size has a right to be. I have used mine in some big rooms and still had sound guys telling me to turn down. If you're playing in venues with microphones for electric guitar, there'll never be an issue with dialling in a great clean tone. If anything, you'll want to run them a little bit hotter (isn't that always the way with guitarists?) because in my experience the best sounds have been just on the edge of breakup.
I generally dial in a fairly transparent clean tone to use as a base for drive pedals, and have found that they work well with pedals. Obviously, there is no effects loop, so that's something to be aware of if you like running pedals through a loop.
One of the most important recommendations I could make with regard to these amps is to consider using a larger cabinet than the matching PPC108 cab. I have been using a Jet City 24S+ 2x12 cabinet, and have found that while it takes away from the portability of the stack a bit, the gains in tone are well worth it.
I can't comment on the auxiliary jack which is included, but I'm sure it would serve a purpose if you needed it, and I suppose there's no harm in having the facility there.
In terms of cons, the tone control is fairly basic , and only allows a certain level of tone shaping, but it does have a good range. In general, I keep it set between 11am and 1pm and find that going outside of this leads to very dark and muddy or ear-piercingly bright.
To summarise, this is a really good amp for the price, and for me it has performed consistently for the past three years without missing a beat. I'm so fond of them, that I bought a second one.