No, go straight to demoing retail skis you might actually buy.
The "performance" skis are usually one step off the bottom of the ladder. The regular rentals are typically the bottom rung. It's a big ladder too. Both are a huge waste of time for a developing skier.
You sound like a typical intermediate skier. If you plan to ski more than 5-10 days over the next 2 years or taking lessons, I would suggest skipping renting or demoing entirely and buy a well reviewed used intermediate ski. Something like an Atomic C9, Omni 5.5, Head i.C. 160, or Fischer RX6 to name a few. Intermediate skis work well for an extremely large range of skiers so you are pretty safe just picking up one a lot of people like, as the differences aren't huge and they are all good.
Although, if you don't have your own pair of boots already, this is the first thing you should spend your money on (and go to a bootfitter unless you don't really care how they fit).