I'm the guy building the iPad panel, so this topic is pretty familiar. I'm currently testing a couple of Amazon buys to see if they work out. For iPads with Lightning ports (everything but the Pro models), I'm using these:
For the new Pro models that use USB-C, I'm using these:
So far I've not had any problems with noise from either unit. That said, I've found that gear that works perfectly in one aircraft (no noise) can cause noise in another. Variations in shielding, grounding, and location of systems (radio, intercom / audio panel, charger, etc.) can make a big difference.
I will say that if you're going to use one of the new Pro model iPads, you'll definitely want a charger that can support USB Power Delivery. Even the 4.8 amp Blue Sea charger wasn't keeping my 11" iPad Pro happy, but the 3 amp charger with PD seems to work quite well.
The biggest unanswered question on these cheap chargers is how long they will last. (I have a spare plus a USB charger pack in my travel kit, just in case.)