Large field of view is a good idea, especially for eye relief. An Eotech works fairly well, and you can mate it with your iron sights. You want something where you'll see your rounds. There are a few airsoft Eotech replicas that are decent, but you'll want to reinforce them with lexan, so they don't get shot out. Companies like NC-Star and UTG are affordable, and make a wide array of products. Anything with zoom will definitely need good eye relief, and having too much zoom is useless. 2x - 3x maximum, or a variable zoom works as well.
A lot of it comes down to your gun and where you play. You may think you're a sharp shooter type, but then your gun has to be long range and accurate, and that can cost some serious money. Is your local fields mostly indoors, forest, open grasslands, urban, etc? Are the local players all rocking $1,500 VSRs and $2,000 PTWs? Check it out first.
Flip-to-the-side magnifiers are extra weight, and mostly useless. I ran one for a long time, and it wasn't a help.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē