Picked up what I'm assuming to be an older model Quantum Iron IR400CX. There's little info on specifications for this reel online. Anyone know anything about this model(specification wise, year of manufacture) and its strong and weak points?

I used to have a couple of these reels.  I found that they were good crank bait/rattle bait reels, as long as I was throwing a half ounce or more.  Distance suffered when I tried to throw quarter ounce baits.  I had one filled up with 10 lb line that I'd use for deep cranks.  Another that I filled with 17 or 20 lb Iron Silk and I'd use that one for rattle baits or square bills.  I got about 4 years out of them and then the free spool button started to not work from time to time.   They got retired, a year or so later I had them rebuilt.  I filled them both with 25 lb mono and now they are catfish reels.  They get used a couple of times per year, when I go catfishing so I don't have to tear up any of my good bass fishing reels.

 

Just checked - mine were the IR4 CW.  I guess the W is the wide spool version of that reel.

 

Bottom line is that they were ok reels that I managed to tear up after 4 years or so.  As I recall, it didn't cost that much to have them fixed.