What do you ride with? What are the advantages/disadvantages to each?

So far; I have only rode(driven?) using handles on a friends buggy.

It really depends on the kites being used. Depower kite require a bar so not much choice there. FB kites can use either. I fly nearly 100% on handles unless using a Depower. The biggest advantage is the added control and ability to rotate the kite on its axis without sending it through the power zone. Stalling or backing the kite up is also a huge advantage on handles. I just prefer the overall control you get with handles over the bar.

Disadvantage with the bar is that the bar is usually quite long and can be a little bit cumbersome to fly hooked into the harness without an extra long chicken loop. I have also had problems of the bar hitting the side of the buggy when trying to rip the kite hard in a turn. For parking and riding the bar is the easiest to use.

Truth is that either one will work great for you so you can fly whichever you feel more comfortable with. For myself and nearly all of the riders in our group, handles is the preferred choice.

I tend to ride either depower or I stick the Ozone Turbo bar on my Flow/Hornet/Beamer. It uses about 70% brake 30% power lines to steer which results in really zippy steering. When I put my 3m Flow back on handles it was disappointingly slow to turn by comparison. (the bar just gives you more leverage and brake input than you would normally use but, of course, anything you can do with the turbo bar you can do with handles and then some. I'm just more at home with a bar. Most of my cruising is on the beach and I find it more natural to have one hand on the bar. If I flew handles all the time I would probably become equally comfy with them. And handles are indeed a lot smaller and less likely to hit anything than a bar. Here's a vid I did messing around in my paddock at home with a 3m Flow on the Turbo bar and you can plainly see I occasionally hit the end of the bar on the camera or downtube. Try both and see what you like - each has their pro's and cons. I've never been in a situation where I've wanted to do something to the kite that couldn't be done with the bar - but I don't fly high aspect stuff either (except for my Century 2 which does NOT like the turbo bar!!!)