Bookshelf vs Bipole surrounds

[Yeha-Noha]

My HT speaker setup:

2 Energy C-200s: LF and RF
1 Energy C-C100: Center
2 Energy C-100s: LS and RS (surrounds, bookshelf type)
1 Dayton 12" Titanic MKIII subwoofer

I have been toying with the idea of replacing the C-100 surrounds with a pair of Energy C-R100 bipoles as left/right surround speakers.

Anyone having experience with bipole speakers and how they sound vs regular bookself (monopole?) speakers, please chime in.

Specifically what are some advantages and disadvantages of using bookself speakers as surrounds vs. bipoles. Are there any compelling reasons to go one way or the other making it worth the expense especially in regards to my HT speaker setup?

TIA -rw