The only one I have any experience with was with the Wal-Mart do it youself variety. It worked well for me. My advice is keep it as simple as you can, and spring for a timer that you can attach to your spigot. It saves alot of time and money.
The downside to drip irrigation is this: If you mulch alot, which you should, and you put the mulch over your hoses for aesthetics, you WILL (unless you're alot more thoughtful than I am) cut your hoses when you get into your beds to dig, divide, plant, etc. Once you cut it, you've got a mess. That is why I eventually abandoned mine.

I have purchased two systems from Drip Works (link below) and love them both. The people there are very helpful in answering any questions you might have. This spring they helped me find some diverters so that I could expand one of my systems so that I wouldn't have to buy a whole other kit to cover an even larger area. I was worried about the drop in water pressure by extending the existing system with another 100 feet of mainline tubing. The diverters did the trick. I highly recommend this company.

Here is a link that might be useful: Drip Works Website

Thanks

I like the mini sprayer head on a stick kind over the individual dripper per plant. They are both low volume systems but the sprayer is easier if you have a lot of plants and the installation is quicker (fewer pieces).
Plus I've had more than a few drippers pop out an create geysers. I'd still use drippers for pots and isolated plants though just not beds where a sprayer or two will cover it.

Generally speaking scottamuss, I agree. However anything that sprays water in the air versus being dripped on the ground and even under mulch is much more prone to evaporational loss than the drippers.