ORIGINAL: ahicks
I went with the IBEC route first time around, liked how it worked (simple!). Next plane, went with just the opto switch while powering the ignition with a diode (or 2!) that drops the voltage down to a safe level for the ignition module. The diode powered ignition/opto switch plan is less expensive, and does everything as well as the IBEC. Just don't try either plan with NiMh AA batteries and bigger servos. NiMh AA's will be struggling to keep up with the amperage required when the servo(s) needs to work hard (eg. knife edge flight). That kind of thing leads to receiver power brown outs and rekitted planes. Lithium or Nicad battery chemistry both work fine!
Glad it worked for you. For 20$ extra the IBEC makes better sense to me and it's complete, RTF, with no additional diodes or anything else needed. For guys who just want a plug and play solution, its benefits outweigh the cost delta
I used 5 cell, 1650 ma NiMH (AA cells) with mine for the first 100 flights or so. The IBEC has a programmable voltage output to the CDI so there is no guesswork as to whether there is enough voltage going out. The NiMH bat worked fine.
I eventually switched to an 1800 2S4P lipo as much for redundancy as weight reduction. Saved another 2 ozs over the 5 cell NiMH. Very sporty