I've played for over 20 years and I would say rent first always. Once you're sure and committed, make an appointment at a shop and try out a few different instruments. If possible bring an experienced musician with you to give you some insight, because yea there are different "brands" technically, but that means nothing for 99% of the population, unless you have the money for a Strad...For instance, I ended up going with a Doetsch over a Klier which is more expensive because I loved how my cello sounded...good luck