The answer is "Whichever you prefer".
You should not blindly trust in privacy policies and promises of not recording IPs. These promises are what is known as "Privacy-by-Policy", that is to say: they have a policy or even a law that says your data isn't collected by them and is subject to certain levels of privacy.
The flaw is the assumption that policy and the law both are immutable and have been "correctly" interpreted; tomorrow a law might be passed that removes all the protection for your data. Infact we know this not to be the case already. Previous work by the late, great Caspar Bowden shows why these policies are mostly meaningless.
Instead you should approach requirements of real privacy and anonymity with "Privacy-by-Design". You should operate such that you need not put ultimate trust in a single law, policy, or entity to protect you.
For example, if you use Tor Browser to search on an arbitrary search provider from a fresh "identity" (e.g. newly started Tor Browser or after use of the
New Identity button) then the provider might log the IP and the search term and your cookies but it would not be able to determine who made the search and infact, all other users using fresh identities would look the same, they could not be distinguished except by what they were searching for. If you made use of
New Identity once you were finished with the first search, then made a second, unrelated query the provider would be unable to meaningfully distinguish between your first search, your second search and the searches of all other Tor Browser users doings the same.
I should point out that I think we should support and respect all providers like Disconnect, DuckDuckGo and StartPage because while their policies might not be the best protection mechanism for you as a user (they can be seen as a best effort in a hostile environment), these companies are taking steps to allow and encourage anonymous use of their services and supporting the technologies that enable it, and that is hugely important.