I prefer beakers over straight tubes.
It probably stems from all of the cheapo bongs around my parts have that egg/bubble shape, so a beaker just looks more bongesque than a straight tube to my brain...
I prefer the higher water volume of a beaker, IMO it seems to add a little bit to its filtration, and I find that with straight tubes, there is a higher tendency for the water to jump up and splash my mouth.
Also, wih the combined larger base, and more water in the bottom (causing them to be less top-heavy) I do quite like that beakers tend to be more stable (but that's also heavily dependant on the design of my beaker... My SYN mini beaker has very rounded edges, and is probably a little bit easier to tip than my EHLE 250ml tube.)
Edit:
Bubblers beat both though IMO.