i have a 4 year old eotech (n cell type) that has probably 5k 5.56 through, 500 + of 308, and now sits on my deer slayer 12 gauge. probably about 100 rounds of winchester partition gold. it's still going strong and has been beat up pretty good. mine gets at least 6 months of battery usage.
if you look around you can find the new xps for 375-425 depending on how long you want to wait. also if you ask for the serial number i am pretty sure you can call with and they will verify it's authenticity, though i am sure its also possible someone could give you a stolen serial number also, thats part of the risk of online shopping i suppose
I don't know where you're finding xps for that price. Cheapest I've found is $465.