Tunze nano ATO was a problem for me. They replaced my pump for free when it failed, but still not a fan. Replaced it with AutoAqua nano ATO and couldn't be happier.
Got a MaxxSpect Jump DC return pump, it's been great. Also have ecotech powerheads and they've been good. I've had huge issue with the AI Nero 3s thoug. After a while they just seize, can't be fixed and have to be sent in and replaced. AI has been great about replacing them, but it's still a hassle.
I've used AI and Radion lights and they've been solid, though I argue the new radions have too much spread at the expense of PAR penetration. Went and found a used G4 xr30.
I got a Magtool nano skimmer for my tank (IM40) and it has worked great.
Lastly, Hanna checkers are good for the ones that use powdered reagent in sachets. But beware the ones that use liquid reagent in dropper bottles (pH, alk)!! They spoil quickly and you can accidentally nuke your tank!