The only time I've seen them play is when they are playing the Rangers, and in those cases, I'm not paying that much attention to them. So, let's look at usage.
Chychrun
EV: 19:52 TOI/G
PP: 2:38
PK: 0:14
I thought the lack of PK time might be based on his usage in other areas, but he has never been a consistent penalty killer during his career. His highest total was 1:30 per game in 2019-20, which was 5th most among dmen on his team that year.
Hanifin
EV: 19:43 TOI/G
PP: 1:43
PK: 2:19
He has the 2nd most TOI/G on the PK, only 19 seconds behind Tanev. His EV usage is about the same as Chychrun's. He doesn't get a lot of PP time, which he won't get with the Rangers either.
23 of Hanifin's 30 points have come at even strength. 18 of Chychrun's 30 points have come at even strength.
Just based on the numbers, I'd give the edge to Hanifin. Chychrun is 1 year younger and has 1 year left on his contract @ 4.6 mil. They are both about the same size. Assuming near equal acquisition costs, I'd say they are pretty close.
The one thing Hanifin has in his favor that Chychrun doesn't, however, is that we don't have to trade for him. We could wait until the offseason and sign him as a free agent.
Of course, there's no guarantee he will sign with us. He could get traded at the deadline and immediately sign an extension with his new team. But if I had to choose a path, signing Hanifin as a UFA would be my option hands down. Chychrun is going to get paid a year from now and could potentially get more than Hanifin will this summer, so the cap savings won't last long.
If Goodrow somehow goes the other way as part of a trade, that could change the equation, but I can't see either team wanting him, or him being willing to waive his NTC for either team.