Things to consider:
- Open curriculum at Brown vs. a more standard set of distribution requirements at Rice
- Northeast vs. Texas location and weather
- Compare research opportunities
- Brown's housing vs. Rice's res colleges
- Compare cost if you are full-pay (and run NPC if you are not. Actually, run NPC anyway...)
- Providence vs. Houston
- Compare social vibes -- Brown's relatively more liberal/hippy vibe vs. Rice's relatively more nerdy vibe.
Both are going to offer mostly small classes once you get past the survey level, excellent academic support and teaching quality, good career/post-grad support, and other markers of quality you’d expect from highly selective private universities.