I used confused.com for years and weighed up who I went with based on price and brand reputation, which usually meant Admiral, Esure or Privilege. Their policies are fine, but you may think the features and cover that a specialist can provide is valuable to you, so it's worth finding out IMO.
I contacted a few of the specialists people on here tend to use such as Classicline, AIB, Bridle, Mannings UK etc and its clear that that the policies are different (as Robertb says). They can include agreed value, choice of repairer, euro breakdown, full comp when driving another car, track cover, plus other smaller things you may value. they will usually cost more, but they may represent better value for money, maybe not, only you can judge that.
I'm with AIB/Hiscox for my C4S and wife's Volvo V60 for £785, it comes with the things mentioned above (except the track cover) and I saw that as better value for money compared to Admiral multicar for around £600.