Spinning reels are heavier, have less power, are harder to cast accurately and give you a lot of line twist.
A bait casting reel is easier for accurate casts because your thumb is on the spool and can stop the bait as it is about to pass your target. Furthermore, the way they are designed, you can make more casts per hour with a bait casting reel. With a spinning reel, you have to commit your extra hand to disengaging then engaging the reel. With a bait caster, you disengage it with the hand that’s holding the rod, and it engage it by turning the handle.
The line twist is a very big issue too. Since a spinning reel has a fixed spool, your reel turns the line around it and this causes quite a bit of line twist. The thing is, bait casting reels might get backlashes in an inexperienced angler’s hands but the line twist issue on a spinning reel is impossible to avoid. An experienced angler can minimize it, but he will eventually have to deal with it.
Another contributor to line twists on spinning reels that doesn’t happen with a bait casting reel is when the angler tries to reel in line while a fish is pulling drag. This gives a lot of line twist but is easily avoidable with proper technique.
Bait casting reels are, therefore, the way to go for your all-around fishing needs. Since you need to overcome the bait casting reel’s spool’s mass to make a cast, it is very difficult to cast light baits without backlashing. Baits weighing in at under 1/4oz are better left for spinning reels. Wind is another situation where a spinning reel can be useful. If you’re casting against the wind, the wind will slow your bait down at a much faster rate than the spool and that will result in a backlash as well.
Any time a baitcasting reels spool is feeding line out faster than your bait is flying away from you, you backlash. It is the responsibility of your magnetic braking system and pressure from your thumb to control the spool speed and prevent those overruns.
And, you can still get an overrun with the DC reels. With that said, I’ve heard nothing but good things about them.