I have 4 of the MB863XF. I absolutely love the blank for what I do. I call it the perfect smallmouth casting rod. I can literally throw anything on it. It's an awesome finesse swimbait rod, spinnerbait, jerkbait, topwater etc.
Never built the 4 power. The 3 has a pretty light tip, so my only fear is it may be a little light in power for a frog, but I enjoy mine so much, I think it's worth a shot, especially for sparse cover.