Is it safer to buy a circular saw with the blade on the left or the right? I'm right-handed
A right-handed person will always, naturally have the right hand on the trigger thus making the right handed blade easier to see from the right side.

For maximum safety, the left hand should also be on the tool.  When it is, the left arm, riding high and forward, will partially obscure the blade and the cutting line from the left side view.

Also, when the right hand is on the trigger (and left forward of that) one might want the motor closer to one's body (than having the blade there).