The current version of Nestopia features
* Completely free to use.
* Efficient CPU usage, for improved battery life on PowerBooks.
* Flexible video display sizes with numerous Blitter effects.
* Sound recording functionality.
* Transparent decompression of GZIP-compressed game files.
* Support for 174 different mappers.
* Support for five additional sound chips.
It is THE BEST cycle-exact emulator for NES on OS X.
The previous reviewer who said Nestopia can't run full screen stated falsely. The free version of Nestopia cannot run full-screen; with the purchase of Emulator Enhancer (which works with ALL of Bannister's 28 current emulators).
From his web site:
This feature set above can be expanded using Emulator Enhancer, a shareware module which adds the following additional options:
* Full screen mode.
* Network play (some emulators).
* Real time video and sound filtering.
* Support for USB game pads and joysticks.
EE is currently available for . If anyone wants to rate EE (based on the customer having to pay for it), this belongs in a review of that software, not Nestopia.
Nestopia even has its own support forum now; use it if you need help with the program: http://www.bannister.org/ubb/ultimatebb.php?ubb=forum;f=36
I rated the Features as low, as Nestopia is missing a few features in the free version -- also, it is currently missing support for zip and 7-zip archives, as well as for Quartz effects and OpenGL overlays.
Everything else, I rated as 5, as there are no other NES emulators that perform as well (on ANY platform) as long as you have a fast enough CPU to run it at full speed.