I only had a couple of irks with the Action Replay
and they can mostly be attributed to my personal impatience. The software that is available with the device, a database system for managing your codes and making sure you have the most updated versions, was fairly straightforward. But I found it slightly annoying that every single time I wanted to view the GBA's database of codes, (not the ones stored on my PC, but the ones inside the Action Replay
cartridge itself), the software had to download all of the information from the cartridge which would take several minutes (even over the USB link cable provided by Datel).
My advice to keep this from becoming too much of a problem is when you first start up the GameBoy Advance with the Action Replay inside it, delete the codes for the games that either you don't have or don't ever plan on getting. After doing this, the amount of time it takes to download the code information from the cartridge is greatly reduced.
Another annoyance with the system, and again I think this has more to do with impatience, was when manually entering a code (on the GBA) it became very tedious having to move around the virtual keyboard to enter names of games and codes. This was very time consuming.
Also, Action Replay works only with GameBoy Advance games, the system does not recognize GameBoy Color or original GameBoy games (that isn't to say that it won't allow you to play them, it just won't have any cheats for them), but according to Datel, this is 'to make the experience all that better for the GameBoy Advance gamers.'
If you have a wide variety of GBA games, and many of them are beating you to a pulp, the Action Replay is a good buy. It will allow you to get past many of the difficult parts of games, and it can be turned on and off if you feel you want to make it through a certain area without the crutch.