I've been a huge Prust fan since his first game here. Should definitely have a spot on our fourth line next year, maybe even our third. Shelley I'm more or less indifferent on, depends on the contract. You can get someone to fill his role for cheap but, with that said, if the contract is fine, then sign him up too.
As a Canucks fan I saw a lot of Prust. He was absolutely schooled a couple times early on by Rick Rypien, but kept coming back; to the point where more recently he was giving Rypien a run for his money. He'd be a good one to keep. I think he can still get better.
Both of these guys play a direct style of hockey. And opponents still have to be aware of them for other reason, it's not like they are goons. They like to pressure the opposition, they're not a bit shy.
Keep them both... this was the 4th line I was envisioning at the beginning of the year... a physical, in your face line that spends a decent amount of time in the offensive zone and can chip in a goal every now and then.
I know everyone liked Betts & Sjostrom, but they didn't intimidate anyone, nor did they drive to the net or outmuscle others for the puck. Shelley and Prust's physicality are part of the reason why their line is so successful. I don't think I've seen an offensive explosion like this on our 4th line in a long time.