I don't know about anyone else but I find it hard to find any critiques if you don't have a subscription :/ Because I am a self taught artist I'm not too sure on what all I'm doing so I really need a few critiques on my work so I know what to improve on.
Even if you have a subscritption, you won't find many people who are willing to give critiques and there are quite some reasons for that. You don't need a subscription, you just need someone who write a critique. But it's time consuming and often enougth people don't know if the person wants critique or not.
dA has a critique function that is only available to subscribers. You can find some groups here that encourage critique on dA as well as critique-oriented threads in the Thumbshare forum.