I've been recently interested in getting a 5.45x39 upper for my AR15. I was interested in a 7.62x39 upper a couple of years ago, but I do have an AK47 perfectly capable. I've been sort of loathing over a Spike's Tactical upper lately (which might be hard to find from distributors right now....but I can still find them). At this time I have no 5.45x39 ammo, but liking the prices I see for 750 rounds just to get going. Asking for opinions (door is wide open). $600-800 for one of these at this time. Low range if from manufacturer or distributor......high end from owners. Those who have one I would appreciate reviews...pros and cons. Not looking for a completely new firearm because I know that would likely lead to hundreds of dollars in mods. Thanks all.