Any disadvantage to splitting for a 1L summer in the 2L job hunt?  Should I pick firms that are very different (different cities, different practice areas, different firm culture, different sizes) or should I pick similar firms to try and decide this summer which one I like best? 

Should I just stick with my favorite firm for the whole summer?

Pay isn't an issue.  All the firms are within a range of a few hundred dollars a week near the top pay for the geographic area.