There is a difference between a conditioner and a polish. A conditioner is basically either a high. low or neutral pH detergent. A polish contains a water soluble silicone that gives short term protection.
If you are using a super sealant like many manufacturers make I would recommend you use a low pH conditioner. It cleans and assists both the super sealant and
drying agent to work more effectively by lowering the surface pH. You could consider using a neutral pH conditioner if you are using a low pH presoak or shampoo but the difference in the cost would be almost insignificant.
If you are not using a super sealant you would get a better looking results from a polish rather than a conditioner but you could also get decent results from a low pH conditioner if you wanted to save a little money since it should cost less than a polish.