By looking at the tension measurements, the Half-Rounds are about 10% tighter than the XL Nickelplated Steel Round Wound and about 5% tighter than the XLS Stainless Steel Round Wound.

I'm wondering if perhaps the core of the Half Round strings might be slightly thicker, as the Half Round strings start out by being just a tiny bit thicker than the gauge they're going to end up.  Here's a brief description of how they're made:
http://www.daddario.com/DADProducts.aspx?ID=1&CLASS=AACA

I would highly recommend that you try out a set of the Half Rounds, just to see how they feel on your fingers and sound to your ears.  Although reading up as much as you can on the product is very helpful, it's no substitute for hands-on use and experience. 

Just for the record, I'm a huge Chromes fan; but Half Rounds are my #2 favorite behind Chromes.

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McSpadden M-12W, SH-12CRs, SH-12KKc
Custom LR Baggs Piezo Bridge Pickup on SH-12KKc
LR Baggs Para Acoustic DI Preamp
DigiTech & Boss Effects, Planet Waves Cables and Picks, D'Addario Strings
SWR Super Redhead 450w Combo Amp with SWR Goliath Jr. III Extension Cab

Also just for the record,  I have been using GSH Burnished Nickel [pure nickel] strings for quite a while now.  I am not disatisfied with them--they are really great strings.  I just got the itch to try something different and thought half rounds looked like they might give me a sound that I might like, since they seem to be between nickelplated and pure nickel which I would imagine to be a very nice tone.