Having hit ROORs before (the real ones with the frosted logo, not the sticker) I can say that expensive glass really is worth it. A good glass on glass bong rips harder, clears easier, and gets you higher without getting water in your mouth. Personally I save my money to spend on vaporizers though. I have a knock off volcano style vape that works pretty damn well, and a standard whip and hose model next to my bed. I recently broke a bong I had had for well over a year and dropped many times. It was a thick, handblown, green piece with a glass-on-glass downstem stuck in it. It finally broke when the cat ran into it full speed and knocked it onto the tile for, like, the third time. When I have to go out any buy a new bong I tend to shop for HVY, WRKD, or similar pieces. I can usually find a HVY with a few minor flaws and no stamp for around $<no goddamn prices - chainer>. They tend to range from $<no goddamn prices - chainer>to <no goddamn prices - chainer>or $<no goddamn prices - chainer>for the newer WRKD ones that are all glass on glass. Glass beats the shit out of acrylic any day in my book, and a good heavy bong tends to smoke cooler smoother. Here's a few things I look for when I shop for a new water pipe. It should be...
-Heavy for its size
-Free of too much work in the tube and bubble (the more detail there is on a pipe, the more stress the blower had to put on the glass and the most likely it is the break)
-Natural ice catch (these look like someone pushed in part of the tube with their thumb, usually just above the slide. I prefer these ice catches because they generally leave more space in the tube to fill with ice, they are less likely to break than the three point style ice catch, and they let more smoke through at a time than the ones that look like a disc sitting in the middle of the tube.
-Free of cracks (check around where the downstem attaches to the tube especially)
Beyond that its just style decisions. What color, what size, that kind of thing. Happy toking!