I have a lever style on my Grizzly G0709, %-C chuck on my Clausing 5418 and a draw-tube style 4-C on my Rockwell 10".
More experienced guys will add to the lists, here's my opinion/experiences:
Lever style Pros:
Quick removal, insertion of stock into the collet. Flip the lever, slide material in the collet, flip it back and you're tight and ready to go.
Accuracy - best. The 5-C collet adapter is directly mounted to the spindle taper. Stack up to the part is spindle to adapter to collet to work.
Lever style Cons:
On mine collet changes are a bit of a pain. Lots of turns on the back side collar to loosen/remove a collet. I made an adapter to spin the draw tube with a cordless drill to speed up the process.
Chuck Pros:
Relatively quick removal, insertion of stock in the collet (not as quick as the lever style). Works like a 3-jaw or 4-jaw, turn the key enough to slide the material in/out of the collet to position, turn the key to lock it in.
Chuck Cons:
Maybe less accurate than lever style. Stack up is spindle to chuck mounting adapter to chuck collet interface to collet to work. If you have a set-tru style collet chuck, it may be more accurate than the lever style.
Really slow collet changes. Mine takes around 20 full turns of the key to remove a collet. I made an adapter out of the 1/4" hex to 3/8" square socket adapter to speed things up.
Draw tube Pros:
For my Rockwell, it's the most accurate. There is not spindle adapter for this lathe (4-C collets go directly in the spindle); stack up is spindle to collet to work.
Pretty quick stock removal; turn the back side hand wheel a half turn, give it a pop on the end to push the collet out of the spindle, position the work and turn the hand wheel again. Not as fast as the lever style, but quicker than the chuck since you don't need to grab another tool before doing the move.
Draw tube Cons:
Slow collet changes. I usually turn the hand wheel and pop the back side to loosen the collet. Then grab directly on the collet and start unscrewing it.
Regardless of which one you get, you will be pleased. I work a lot with aluminum and brass, never a mar on the surface using a collet. It's really nice to take work out of the collet and go back later and have it well under 0.001" off center. My main lathe is a Grizzly G0709, but the Clausing 5418 gets a lot of use too. I leave a 3-jaw on the G0709 and a collet chuck on the Clausing.
Bruce