i have about 4 of the primary arms red dots. for the price i acquired them ($60) they are excellent and reliable.
i have a vortex sparc. it's fine but i don't think it's worth the $200 that i paid for it. if i had it to do over again i would've bought 3 more pa red dots instead.
i also have an aim point pro that i snagged several years ago for $360. this thing is indestructible and i wish i had the cash to buy about 4 more. the price has gone up a bit.
i've had (or still have) some others too: a docter reflex sight, a lucid hd7(?), some cheaper crap. in the future - i will only buy primary arms or aimpoint depending on my budget.
edit to add: there's a reason why - over the last 3 years - the aimpoint pro (aco too) and the primary arms sights have gone up in price while most others have come down.