I think Orion meant that if it takes a year for someone to read your MS, it might suggest the MS is tough to read. But I'm not sure that is entirely accurate. I think definitely sometimes that can be the case, but I had a friend that I gave my at the time unpublished MS to read, and she started it but never finished it. Now the book still got published, and others seem to say that it is good, and when it was out in book form my friend did read it and like it. I think sometimes being given a MS can seem daunting. It is also more awkward physically to read etc. It isn't quite the same as a book.
I guess the answer to your question is another question. Why did you send your MS to the betas in the first place? Was it to get some genuine input, or was it to just get a more "did you like it" kind of thing? Personally I give my work to betas with the intention of doing more work upon its return. If I had a work out therefore with betas, I would wait on querying because I would know I still had work to do on the MS. Now, in the case with the gentleman who was ill, you may have to forgo him as a beta, but maybe you could talk to the others, explain your situation, and ask if it is at all possible for them to focus at bit more on your MS so you can get it back soon.
As for "the agent will ask for revisions anyway" thing. That is a very dangerous train of thought. First of all an agent might or might not, there is no guarantee. But second of all you have to pull your own weight, you have to submit the work that is the best you can possibly make it. Yes an editor will probably see things you won't have, but you want the editor to be working with as perfect an MS as you can deliver them. Besides, don't you want as much control over your work as possible? Seems awfully odd to want to take what little we have and hand it over.
Aside from that, what's the rush?