Also agree. The Westin is towards the east end of Temple Bar which is your main strip for all things tourist. IC is in a quiet area.
If you want to have fun, see the tourist stuff, etc - Westin.
However, keep in mind the IC is near a DART station, and you can always take DART up to Tara street and be 5 minutes from Temple Bar. So, if you have a reason to prefer the IC and are OK with that, it may be worth it. Do keep in mind the hours that DART runs.