I've been writing with critique groups for about six years, both online and in person. I love working in both arenas for various reasons. I'm a pretty social person and love collaborative work, so that makes a critique group a great fit for me. Also, I don't let my husband, or my sister, or my parents read my work. If you're letting your family read your work, don't believe a word they say. Just thank them and find a critique group. Or, an editor. And I'll bet that if you seek an editor too soon, s/he will tell you to find a critique group. Because you need to hear the truth about your writing.
The truth about your writing will come out differently online than in person. One of the things I like best about my online critique group, is that I don't ever have to look anyone in the eye. Because I can't see anyone on the verge of tears, raging, or rolling their eyes, I'm a lot more direct in my suggestions. Because everything is written down, you can choose your critique points very carefully.
In person, I'm much more careful about what I say and how I give suggestions. The "sandwich method" is recommended: praise, criticism, praise. It can be laborious. But, there is usually someone to back me up or refute my suggestions as needed. Discussion ensues. Perhaps we discover a new idea altogether. It's easier to ask questions and get answers.
Quality and Specification
I write contemporary young adult fiction. That's pretty niche-y. I also live in a flyover state where conferences are sparse. I'm extremely lucky to have found a writing group that meets in person, and that can give me insightful feedback on my genre-specific writing. I've been in groups that looked at everything from poetry to non-fiction to fantasy to picture books, and while there may be sparks of insight here and there, getting solid feedback regularly was impossible. Besides that, I learned very quickly that people have widely varying goals for their writing, and are at widely varying stages of the publishing game. You get all kinds in person.
An online critique group pulls talent from all over, which makes it much easier to find people that are writing similar things, and that have similar goals, and are at a similar talent level. Writing forums such as NaNoWriMo and Verla Kay's message board are great places to start looking for writers with similar needs.
Timeliness and Deadlines
I've found its easier to keep motivated in my writing with my in person group. I have to go and actually fact these people, so I prioritize my critiques for them. I also know that if I want feedback, I've got an actual deadline. I have a stack of papers that I physically see. I know I need to attend to it.
While the deadlines are technically the same online, I tend to be more willing to shoot that email that says, "Hey, I'm backed up. Will get to your critique soon." Again, I can't see the rage and eye-rolling. And the typing of the critique just takes longer. I swear I read slower when I'm reading on screen, too. I'd much rather read and critique on paper. And when that paper isn't sitting in front of me, it's so much easier to ignore the work.
So. To get the most out of myself as a writer, I use both kinds of critique groups. I also hit the conference scenes, attend workshops, keep my eye on a few writing blogs, and attend some Twitter chats now and then. Writing is no longer for the solitary.
Jody Sparks is a struggling writer who knows her craft has improved because of numerous critiques and critique groups. Follow her on twitter @jodysparks