I've a Juwel tank, a vision 260.
The filter IMO is pretty good (lots of volume of filter media, flow rate pretty low) for an internal filter. Not as good as an external in terms of filter media volume, admittedly. I like a lower flow rate as I keep fish from slower-moving waters, so less current but enough water turnover through the filter to keep water quality good. I also like that it's fixed in place, as it's pretty much where you'd end up putting a filter anyway and no danger of the suction cups you get on many internal filters slowly losing grip over time - this happened a lot with my old fluval filter at least, and it was easy enough to fix but irritating.
The heaters are as good as any others, really. Nice that they're tucked away in the filter box as less chance of damaging them and with a good flow of water across them.
The lighting is fine for me - I grow plants in a very low-tech way, so a lower wattage on the lights doesn't give me a problem. Not too difficult to upgrade.
The stand isn't the prettiest /best made on the market, but to be fair, it's pretty typical of the price range. Sturdy enough to do the job. The canopies are pretty inoffensive, too, a lot less "clumsy" looking than many tank sets with more expensive stands.
I reckon they're pretty good - there are undoubtably better tanks on the market (particularly if you buy everything separately and get a decent joiner to make the stand...) But, these are invariably more expensive, often a lot more expensive.