It's really not opinion, at least 99% not opinion. There is little doubt that a dedicated tool for each job is better. With that said, there are many excellent jump break cues. And if you have one you may never find dedicated cues you feel perform better than your combo cue. Maybe a J/B works just fine for you.
I'll give another shout out for Alex Brick. Performance to price, its like he's giving his J/B cues away compared to anything else.
The Players HXTP J/B is solid as well and only $200. It's cheaper than the Brick, but not quite as strong for either purpose.
Andy Gilbert makes a hell of a J/B cue at around $450 that plays well too, and Steve Lomax J/Bs are always well reviewed.
The fact is, jumping and breaking are far more about technique than having the absolute best jump and/or break cue. I use a J/B as opposed to dedicated cues because I've grown tired of carrying so much shit with me to play pool. In fact, I'm so lazy now, I'm using the Players J/B as the only butt I carry and I swap between a J/B shaft and a playing shaft.