I cannot vouch for them personally, but was pleasantly surprised at how loud one is — this being in a braai environment, with noisy kids etc. etc.
A friend has a single, and it does what one would hope for, in terms of background music.
Could imagine a pair doing nicely — but would agree that unlikely to match the sound quality/profile/stage of physically bigger speakers.
Compared to a similar sized speaker, from what I have read/seen/heard, think the HP mini easily takes the win, but again, that's a low bar.
If I were to see some at a discounted price, would probably grab a pair for my kids' rooms.