Just wanted to throw this out there for those wondering about any subtle differences between the 630 and 235 (other than the obvious optical HRM and advanced running metrics).
I returned my 630 for a 235 and got it last night. The first thing I noticed was the band. The band on the 235 is 10000% better than 630's band. It's a softer rubber and is so much more comfortable. There are also more adjustment holes. I'm sure they did this due to the unit needing to be more snug than the 630 but still. The difference in how much more comfortable this watch is vs. the 630 was really surprising.
Also - I never thought I'd say this, but the interface is better too. The touch screen on the 630 just didn't add much to the watch for me. I may be hallucinating as I'm sure the screens are EXACTLY the same, but the screen on the 235 seems sharper with deeper colors (reds are deeper red). Who knows, the 630 is a touch screen so maybe they were sourced differently.
Lastly, It also feels slightly bigger which I love. I have large wrists.
Anyone else notice these things?