First, ask yourself what is the main purpose the Bar will be used for. Most Brands Bar’s range are quite wide and you could buy a bar just cause you like its pics, while you should be informed about all the Bar’s specs in order to know if they really match your needs.
Do not forget about the main IWF regulations: a Men Weight Lifting bar must be 220 cm. long x 20 Kg. x 28 mm. diameter, while a WOMEN one must be 201 cm. long x 15 Kg. x 25 mm. diameter. To teach WeightLifting skills, shorter, fatter, lighter bars do not work at all. Do not stick at the Max. Load data: always ask the Tensile Strength of the steel bar. It shouldn’t be never lower than 190.000/200.000 PSI.
Unless you are looking for a Power Lifting Bar, always ask for a squat-knurl-less shaft. Finishing of the whole Bar: Bright Zinc Plating is the one! Black Zinc Plating shall fade in a while, Parkerized, Hard Chromed, NP Plated, Black Oxide shall drive you crazy with rust spots! Polish Chromed shall flake and then rust. Some shafts are black coated and they look quite fine, but always ask for e-coating. Standard liquid coatings are not durable at all.
Bushings or Bearings? Bushing shall work better for classes and a high number of reps/drops, while bearings shall work perfectly for Weight Lifting skills on a WL platform. Should you go for Bushing: just bronze and oversize, please. Should you go for bearings: oversize needle close to the shaft and 2Z balls close to the bar’s ends. Last but not least: the price of the Bar! There is no average ref, but, a good WL Bar can’t be a cheap bar. A cheap bar shall get bent, or, even worst, broken, after some WOD.