As has been said in the other threads, the older minis often had issues with accuracy being bad to terrible. Some shot ok, a decent group of them shot good for the first couple shots before the barrel got hot, and others couldn't hit a barn from the inside.
Newer minis seem to have sorted out a bit of the accuracy issue. Some still don't shoot, but most mass produced rifles have a few that won't shoot, regardless of brand.
The biggest problem I have with them is their price. I know this again is an issue that has been beat to death. To me, I really like the AR platform. Due to that if prices are close I would probably splurge and buy the AR. Locally and in general the cost of a Mini has crept closer and closer to that of a budget AR. Still cheaper for the most part, and certainly cheaper when you look at non base model ARs. To me I still would rather build the exact AR I want even if a bit more pricey than pick up a new mini. When the current production minis hit the used market a bit harder I will be looking to pick one up. I think they have come a long way since the older options and once I can pick one up for the prices the older minis are selling for I really do think I will get into one. Until then I'll stick with a new upper for the AR.
Nothing wrong with the mini. I just would use it for the same purposes an AR would be used for, in which case at the new prices of both I will stick with the AR. For how long the design has lasted they must have made a few customers happy over the years.