They're not that well built from what I've seen of the internals.
Reliability is a major Achilles Heel, which makes them a false economy as well, and the usability isn't that great either. The biggest stumbling point to me though, is if one tool breaks, you loose the use of the others while it's non-operable or under repair (don't try to use one tool to fix another, as you don't want to solder on live circuits).
Best to have separates. Which also allows you to spend the money on quality where you'll use it the most, namely the soldering iron. For example, you can get a Hakko FX-888D for under $100, and you can get a well built separate hot air station from Quick brand, such as the Quick957D on the bottom end (~$100), or a Quick861DW (~$235) if you want a professional grade station without paying Hakko, Weller, JBC, Pace, ... prices.
As per desoldering wick, you need to buy quality, such as Chemtronics, Henkel/Multicore, or Techspray. Same goes for your solder and flux (Kester 44 in 63/37 alloy & 66 size flux core in whatever diameter you want, and MG Chemicals 835 will fill these needs well respectively for example).