I see nothing wrong with using your ISP's DNS servers.
OK, I guess if your ISP is snoopy, they could see what domain names you are resolving, and thus infer things about what web sites you are visiting and such. But, look, you already have to place a lot of trust in your ISP. If they are snoopy, they could also just spy on all your traffic. So, unless you have some particular reason to believe your ISP is targeting DNS traffic to its own DNS servers especially, I see no particular reason to avoid your ISP's DNS servers.
You could set up your own local caching DNS server, if you want. I don't think it'll make any appreciable difference to your privacy. It might improve performance, if your cache is more effective than your ISP's cache. On the other hand, it is also possible it could hurt performance, because of the increased number of recursive queries that will be triggered.