There are pros and cons. And, yeah, they actually seem contradictory. It's your call, and a tough one. As you consider the move, just a couple of things to keep in mind:
Half the kids in level 5 are out by 6. (Here are the USAG Stats on number of participants). In light of this, consider the best decision for right now, not some long term goal.
Level 2003 2004 2007 total average % previous of level
5 17841 17416 17400 52657 26329
6 10779 8772 8832 28383 14192 0.54
7 8335 6725 7357 22417 11209 0.79
8 6517 5432 5333 17282 8641 0.77
9 4308 3543 3284 11135 5568 0.64
10 2319 1900 1691 5910 2955 0.53
Elite 163 143 97 403 134 0.05
How devestated would your daughter be if she tried level 4 over the summer and had to drop back or if she could get the skills but not polish them enough to place during competition? If those things wouldn't bother her, definitely try it.
I had one kid progress through the rec program (even took a 2 year break in there). She's spent a year at each level and done very well. In here career, she's had two meets where she didn't finish in the medals in all-around, and one of those she was competing with a broken metacarpal. She's currently finishing her gymnastics "career" as a level 8.
My other kid skipped most of rec and did what other people are calling hot-shots or some other fast track. She did a year of 4, one meet at 5, then moved right to level 6. She certainly was lacking some of the polish of the girls who hadn't skipped levels. She didn't place well as a level 6 and the optional coach had her work cut out for her when dd2 started training 7. Doing well as a gymnast takes polish, not just skill acquisition. Sadly, taking the time to polish is not nearly as much fun as learning the new skills, but it has to be done. Please don't rush simply because your fear your daughter will get "bored."