I am a curious guy. I decided to buy both games (Oracle of Seasons and Oracle of Ages) because I figured they are less than 5 bucks each. Might be a cool novelty.
Hardware
The cartridges arrived today and they look very good. The labels are finished in a glossy print that looks very detailed to me but not as good as an original GBA label. The cartridges themselves feel very solid, there are no gaps, sharp edges or protrusions, nothing is rattling inside. I can see a battery inside both of those cartridges so they are most likely SRAM based. One thing I noticed is that the cartridges stick out about 1mm further than original GBA carts - nothing you'd really notice just casually looking at it but definately noticable when you move your finger across the top of the GBA.
Software
The games are, as expected, just GBC roms running in an emulator (Goomba Color 12-14-14 to be exact). Not exactly a surprise, I was hoping they had found a more sophisticated way to get them on a GBA, though. Because of the way they are made, they should be running on anything that runs GBA cartridges. I have personally tested them on a GBA, GBA SP, DS Lite, Gameboy micro, Revo K101+ (GBA clone) and a gamebox (another GBA clone) and all worked fine. The usual Goomba Color limitations apply, i.e. you can not run the game in full screen and as far as I know you can not link these games up. The ROMs used are the US release of the games therefore there is no way to change the language to french or german.
If you want these games you are probably better off getting the GBC originals (or reproductions if you like) over these, unless you do not have any Hardware that plays GBC games or a native GBC emulator.
All in all the 10 bucks i spent on these didn't put me on the streets and it's sorta funny to have them. I am not going to buy any other "GBA Edition" games, though.