I'm not an engineer, so I won't pretend to understand the parts and design process that goes into making a bar, but I will say that I have experience with a Pendlay bushing bar. When I started, that was my first bar. For what I knew (not exposed to yet), it felt fine. I'm not sure if they started to use the same steel as they do with the bearing bars, but my first bushing bar started to lose some of its "feel." I have not had the same issue with the bearing bar from Pendlay.
If you can spare the extra $150, I would go for the Pendlay bearing bar. It's not as pricey as the others (Eleiko, York, Werksan, DHS after shipping) and they offer a lifetime warranty. In addition, it ships free. For the economically conscious person, you will enjoy that bar.
As for the differences you'll feel, the bearing bar has a moderate whip (more so on the favorable side), the knurling is less aggressive than an Eleiko (and much less than the York), and the spin is pretty good. Once you've felt a bearing bar (and you have with Eleiko), the bushing bar leaves more to be desired. I would say the bushing bar is fine for CrossFit and generic use; the bearing bar is more for the weightlifter. The spin eases the strain on the wrists, elbows, and shoulders.
I hope this helps you. Best of luck and enjoy!
Javier A. Sanjuan
Olympus Barbell Club
Dear God, please help me lift heavy and be awesome. Thanks. Amen.