First Smith incoming thanks to y’all

Back in January I was browsing through here as I was bored and came by a post about Sportsman Outdoors Superstore that advertised a FDE M&P compact with a Crimson Trace red dot for $500 before rebate. Hope to get it in next week but am wondering if the red dot is good enough to use for the time being or if it’s like Glock Factory sights and is just there to hold the spot for the next optic. Trying to spend my rebate money before I get it essentially. It probably won’t replace my G48 or 1911 CCO for carry but I wouldn’t be against the idea if I like it well enough. Now the mags. I’ve been spoiled by cheap factory and magpul Glock mags so seeing the $35-40 for M&P mags was a surprise. Is that the price they go for these days? Are the $20 Armscor any good? Thanks in advanced!