I’ve never really been able to tell a functional difference between the Chorus and Record (but I’ve never had either new out of box) and I too, like the alloy look over the Carbon. The Record group has the edge with aesthetics though, in the hidden 5th spider crank and, for me, it’s worth mismatching a group to have those cranks on the bike.
Robbie, the carbon rear triangle bonded to aluminum, occasionally steel, front, was a thing in the early 2000’s. I guess the idea was to make the ride of aluminum a little more forgiving and give some of the pizazz of a carbon frame without the high cost of a full carbon frame at that time. There was a lot of argument that it was a marketing gimmick. I still have, and really enjoy, my Wilier Alpe D’Huez from that era. I’ve never ridden a comparable full aluminum frame to see if there’s a difference. Anyway, I guess full carbon frames got cheaper or maybe people just stopped buying that style.
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N = '96 Colnago C40, '04 Wilier Alpe D'Huez, '10 Colnago EPS, '85 Merckx Pro, '89 Merckx Century, '86 Tommasini Professional, '04 Teschner Aero FX Pro, '05 Alan Carbon Cross, '86 De Rosa Professional, '82 Colnago Super, '95 Gios Compact Pro, '95 Carrera Zeus, '84 Basso Gap, ‘89 Cinelli Supercorsa, ‘83 Bianchi Specialissima, ‘VO Randonneur, Ritchey Breakaway Steel, '84 Paletti Super Prestige, Heron Randonneur