Juwel tanks are IME usually the better made of the package tanks, unfortunately the filter isnt genrally the greatest, although if only going for a general community tank with no overly messy fish, they are good enough, but they do take up quite a bit of space in the tank.
So I usually buy Juwel tanks, remove the filters and put on a decent external, eheim externals being the best brand, the classic range are reasonably priced and run for years without problem.
Fluval tanks are also solidly made, the problem being with the hoods which arent so well made, more flimsy than the Juwels and the cabinets not as sturdy (this is my personal opinion btw), the larger range of Fluval tanks come with a fluval external the smaller size tanks come with the fluval internals which are pretty good for internal filters.
Aqua one tanks again are fairly sturdy tanks, the evo range coming with an external filter, the others with internal trickle filter systems, which can I found have a habit of clogging and I found them annoying with the constant trickle noise of the water re-entering the tank. But can be more trickly to fit an external too because of the hood design with the trickle system in it.