If you get radio triggers (probably the best invest, imo), you can use them with your speed light and studio strobes.
I have a mixed kit of several speed lights and mono lights. The mono lights can be a pain, but have much more power. Speed lights need batteries and you can go anywhere. If you were to take the bees to an on location shoot without power, you'd need a large battery for them.
It's all about portability vs. power.
If you haven't, check out
http://www.strobist.com . There's a whole cult dedicated to getting professional results with speed lights.
If you have some more money to spend, check out Elinchrom. They have some entry level digital strobes that are more consistent than the Bees. The D400 is a great light and is 400w/s compared to the B800's 320w/s. Elinchrom's modifiers are a bit more expensive, but there's other companies like Amvona that make cheaper modifiers that can work with their lights. I think they're like $320-$350 a light compared the the B800's $270-$280. They don't have as big an issue with color shift at the lower powers. Also, the Bees are wired some way that makes it so they have a shorter flash duration at higher powers. This makes them especially useful if you're planning on shooting sports and action. The downside of the D400's is that at full power, their flash duration is 1/800, which might not be fast enough if you're shooting something that's moving fast. The Bees ar 1/3300, iirc. But the Elinchrom work like a normal strobe should and as the power drops, the flash duration gets shorter.
In fact, I was thinking about buying a few of Elinchrom's Ranger units is people start paying me more.