I've found the sandbox logs to be very useful in debugging misbehaving frameworks, typos, etc. - the usual n00b stuff I suppose.
I've got a vagrant stack running quite nicely. If i port forward I can view marathon and mesos UIs nicely from my host, but I can't get the sandbox logs because 'slaveN' isn't resolving from outside the Vagrant stack. I was a bit surprised because I didn't expect to need to reach the slaves directly. Does each slave expose a webserver to serve up sandbox logs or something? Just trying to work out how/if I can map things so that UI can be tunnelled easily.

