jzintv4droid is the easiest option for Android. You can get it from the Google Play store. You just have to have the grom.bin and exec.bin files (along with ecs.bin for ECS games) in the same folder you try to launch a game from. Games can be in .rom format or .bin+.cfg format.
The only disadvantages with jzintv4droid are based on the fact it's a fork of an earlier version of jzintv, so Ms. Pac-Man doesn't work, and it also doesn't support JLP titles. Although you might not care, the emulated ECS keyboard echoes an equal sign if you try to input a plus sign, so don't bother trying to write ECS BASIC code in it.
The best solution is to do what I did: set up a Linux environment with an X server, and compile and run the latest version of jzintv in there. It was made to be a full-blown development environment, so it might be a bit intimidating, but I created full documentation to help you set it all up if you're interested.