Hey Telerophon,
The SD2SNES is a flash cart developed by ikari_01. Krikzz offered to produce and sell ikari's sd2snes flash carts exactly to specification because he understood the importance/potential popularity of a flash cart capable of simulating (almost AFAIK) all expansion chips used during the SNES's lifetime.
The super everdrive and SNES powerpak are pretty similar in terms of specifications, and both come included with an actual DSP1 chip for playing Mario Kart/any other game that used that chip if you so desire. Other than that they both pretty much don't offer any sort of compatibility with games that used any other expansion chip. In terms of pricing the super everdrive usually is a bit cheaper and also comes with the option of a bare PCB without a case. If you are choosing between the two, you could get the SNES powerpak to match up with the NES powerpak or the super everdrive if you want to use an SD card instead of a CF card.
The SD2SNES is a totally different animal, however.
The thing about this flash cart is that it contains a large FPGA (with a respective higher board cost) that is capable of simulating all expansion chips used with SNES games. Right now only DSP1, 1B, 2, 3 and 4 as well as CX4 (megaman X) along with a few others such as byuu's MSU1 are supported, and much like with the NES powerpak a simple software update will remedy the situation as ikari figures out how to program the FPGA to simulate each expansion chip. He's currently working on superFX, which when complete will allow you to play all games that used that chip (including Star Fox 2!) on real SNES hardware. Adding superFX support when available will be done simply by installing a downloadable software update placed on an SD card through the cartridge's firmware.
SD2SNES website: http://sd2snes.de/blog/
SD2SNES Features and current expansion chip compatibility: http://sd2snes.de/blog/status
Note: I ordered an SD2SNES from retrogate a few days ago.
Another note: Krikzz has a very good reputation in the retro console flash cart market and he manufactures both the Super Everdrive (which he designed himself) and the SD2SNES.
Oh yeah, and feel free to hop on #famitracker if you have any other questions and I'll try my best to help out if I'm around.
Last edited by Zephemeros (Oct 15, 2012 11:25 pm)