ANd here's my story. My ms was with a top agent (A) exclusively, but no deadline had been prearranged. She'd had it for 4 weeks when another agent (B) requested it. I told her the situartion; she advised me to give the agent A one more week, and if she didn't want it to give HER (B) an exclusive. She said she'd read it "in a few days". That's what I did.
After two weeks I gently asked for feedback; I told her that other agents were interested and I'd like a decision. She said "she hadn't had time" but had started, liked it, and needed more time. I told her she could have that time, but no longer exclusively.
She said she'd get back to me but let her know if it was accepted anywhere else. That was MONTHS ago, and I haven't heard back. Other agents I'd queried said they only wanted it exclusively, and to let them know when agent B had finished.
In the meantime, I've started another book as I believe if so many of them are dithering something must be wrong somewhere; the topic, I guess, just is not commercial enough at this time. SO I'm not particularly upset. But I do think agent B was extremely unfair!