Primary concern for me would be which way is the safest. Coming in at a close second...which is less boring.
For me, in most cases, swimming in and clearing deco would be better than shooting your DMSB, clearing deco and doing a surface swim.
In the case of the first scenario:
1. There tends to be more to see
2. Who wants to do a surface swim if you do not have to?
3. Some of my best dives have been in 30 feet or less of water.
If I am hanging on a line, I can almost guarantee that I am itching to get to the surface...checking my computer and seeing how much longer I need to be under. I clear my deco, add my safety stop and take my dead time to move that last 10-15 feet to the surface. On the bottom, I am more likely to clear my deco, perform my safety stop (or in this case...poke around and perform a safety swim) and then stay there as I get caught up in looking around. As long as I have usable air, I am blowing bubbles. Tends to be inherently more safe this way in that regard plus you see more.
And have I asked...who wants to do a surface swim?