What would be the benefit to a "match grade" upper? I'm not looking to get into the cheapest thing I can get, but I want a good reason for the extra $$.

Looking at the Troy/BCM flip up rear BUIS, cursory research says it's got a pretty good rep. As an alternative, are there any reputable and reliable BUIS that are elevation adjustable? I'd like to retain capability where possible (though eventually the plan is for a main optic sight) though I guess in most cases the IBZ gets you through most of your engagement envelope. Seems like LMT makes a railed rear sight feature identical to the A2, but it's fixed, not flip down. I could still shoot regular irons High Power matches with that. Hmm...decisions, decisions.