boots are more important.... i guard mine with my life .. as for rental skis . if you are not happy with a pair tell them to change them .. if you are in ski school ask yuor instructer to sort it out ...
Just back from Borovets, the ski hire dept in the Samokov were fine they give me the wrong size ski but changed them for what i wanted no problem. We all have our own boots to make sure you have the comfort ( well as far as ski boots can be comfortable)
We go to bovovets evey year skiing and find the ski hire shop very help full they will chang your boots or skis as many times as you like and they try to help you get your problum sorted . All you have to do is ask.
Been to Boro the last two years (only skiing i've done).
Last year on one run it was really icy, i was skiing with my bulgarian friend who is also a very good instructor and he offered me his ski's as i was not too happy with conditions, so they must make a difference!
I've got my own boots this time but heard you can get your rental ski's serviced for about 10 lev so thought i might do that.