red sensor is pretty similar as far as VLT. ones 60% and the other is 70% so something like that. but i just find the red sensor to be crisper is lower light conditions....heavy snow, fog, even night. its also not bad on partly sunny days but it will be bright on blue bird days. i have a photochromic sensor mirror that ive used last season and will continue to use this season. but over all i prefer the sensor mirror as my one stop shop. it does very well in every condition and if i could only use one lens for an entire season it would be the sensor mirror. i dont have a lot of time with the ignitor lens, i have them for both my I/O and prophecy, but over all i like the sensor mirror better, and if its a sunny to mostly sunny day ill use green sol X which is my favorite in those conditions. hopefully that helps and again thats just what i prefer. when you go to try them on, ask if you can go outside and see how they are during the day. depending on where you live plan accordingly. if its mainly cloudy during the winter....east coast, then go on a cloudy, snowy, overcast day. if you get a pretty even mix or lots of bluebird....western resorts, then again plan accordingly. if you get the I/O you can get the best of both worlds. for the most part any I/O that comes with a green sol x will also have a sensor mirror with it, or if it comes with a red sol x, it will have a red sensor. if it comes with an ignitor its either a sensor mirror or rc36 lens. my favorite combo would be green sol x and sensor mirror.