Yes, I would buy it (I was actually given the HoI 3 Collection as a Christmas gift by my younger brother, who is not as attached to his money as I am to mine). I don't often buy games (at least not new or within the initial release period; more likely after the price has "cooled"), but with foreknowledge I would definitely buy HoI 3 if I were in the market for a WW2 grand strategy game.
Just a heads-up, my copy of the "Collection" edition didn't include a physical manual. Not sure if this is normal (when I got Victoria 2 the previous year... again, a present; I'm starting to wonder if my brother has bought shares in Paradox ...it included a slender "Tech Guide" which didn't actually list the research options as you might have though, but gave descriptions of the different pop and industry types).
Just a heads-up, my copy of the "Collection" edition didn't include a physical manual. Not sure if this is normal (when I got Victoria 2 the previous year... again, a present; I'm starting to wonder if my brother has bought shares in Paradox ...it included a slender "Tech Guide" which didn't actually list the research options as you might have though, but gave descriptions of the different pop and industry types).