I haven't owned both, so don't really have anything to offer about the chamber type, but I can say the suction type I've used for years is great. Ziploc/Saran will simply not keep your food fresh for as long as the vacuum sealer will. Some might say the bags cost more, but I say it makes up for it in the lack of food that needs to be tossed for having gone bad.
The chamber type will probably take up more room, whereas the suction type is small, and always at hand on the kitchen counter. It holds its own roll of bags, and the boxes of refills from Costco come with a wide roll, narrower roll (for when using a wide one would be a waste), and some individually pre-cut bags as well which are always handy.
The suction type can also re-seal some commercial bags as well, like chip bags and the like.
I've used mine to seal (essentially laminating) documents like my ATT and registration slips, and to nicely pack up bulk items as well (being careful not to suck too much air out of the bag resulting in a puncture for certain items like bullets
). I wouldn't be without one for day-to-day use.
I suspect the chamber type would be better for speed/volume, as that's what the local deli's use. The bags also look more professional, as the consumer version (suction) has zig-zag air lines/pathways, rather than being absolutely transparent like the commercial variety. Which brings me to another point - those commercial clear bags seal right up to the item that's sealed, and to get at them, you have to cut right up to the item. With the consumer-grade bags, you just need to cut into the bag anywhere, and it will let air back into the bag (allowing you to re-use the bag by re-vacuuming and re-sealing it). This is nice for an item like a large block of cheese that you're likely to access multiple times and re-seal after.