Windows only and closed source sadly. Far, far better than Yabause.
It had a recent major update, 0.12, which improved compatibility for certain games but broke others. It added support for some of games like Astal (needs "Enable SH2 Cache"). Keep both versions, pre- and post-0.12 just in case. To raise compatibility, you can try with "No Bios" enabled or disabled, and you'll want to start with the MaxCompatibility (slow) option, then try with the faster options (that do not always work).
The emulator needs an external virtual drive to read iso files. You'll need to close and restart the emulator (as it says in the Japanese dialogue popup appearing) whenever you modify the options for them to take effect.
Even though it has a "No Bios" option, you'll sometimes need the bios files, of course specifying the correct region in the options.
F7: Pause and Load State (Press 0-9 to choose)
Shift+F7: Pause and Save State (Press 0-9 to choose)
Useful for sprite rippers are the numeral pad keys, which disable layers. Keep in mind this often causes 3D games to crash, and they already have lower compatiblity than 2D one when it comes to general emulations.