We transitioned our son to a toddler bed at 20 months. He was trying to climb out of his crib. For almost 3 months, it was like heaven to have him sleeping again! And then it became a nightmare - he would be up ALL NIGHT, over and over. We did EVERYthing the pros say to do, but it didn't work. So we put him back in the crib. He started sleeping like a dream again! Then he tried to climb out and fell on his head on the hardwood floor (he was fine). We got a crib tent, and he freaked out a little but was fine. Then we went to Kentucky for xmas and he slept in a regular crib (no tent) there for 8 nights, it was awesome! But when we got home, he freaked about his own crib with the crib tent. So we got rid of the toddler bed and put him in a twin with a rail, and it's been great. He is older now so he's not getting up. He even waits in bed until his "tweet tweet" music comes on at 6am, because he knows he's not allowed to be out of bed before 6.
I am telling you all this because I think you should try the bed, it might help. But you might have to go back to a crib, you might not. You might have to try mattress on the floor, and then a bed rail up higher (they're only $20 or so). Our son is a restless sleeper so we had bumper pads on the crib up until the 20 month mark. When they weren't on, I would hear him slam his head into the rails, and then he would wake up!