Eh. Wetware is cheap (hell, it makes more of itself even when we don't want it too), and does a fair job of mending itself. Hardware is expensive, though it has the advantage of being easier to power and is lighter.
I think if you recognize the advantages and disadvantages of both you could effectively use either of them. Of course doing that might not be considered "humane" by our current standards.
I think the real hope is waiting for hardware to master the "fixing itself" problem (preferably by conquering replication, which would also largely fix the expense problem). Little need to drag along the wetware at that point though.
Wetware has life-support requirements. Even minimal wetware, though in spore form it may travel well. Depending on your definition of wetware, so long as you've got an ambient solar flux, power isn't hard to arrange, and it's possible that thermal sources (similar to existing deep-space power units) might work as well given what we've learned about deep sea vents and subterranean microbes.
Sentient wetware tends to bring along baggage of requesting rights and such, which can be expensive to provision.
Hardware can both survive and function in a wide range of extreme environments.
Cheap? I guess you don't have kids. There is a huge time investment getting an 8 lbs eat-sleep-crap infant to something that can operate simple machines.
Cheap in the sense that we have lots of them that can be put to work for a pittance. I suspect there would be no shortage of fully developed humans willing to go on "one way" missions to Mars or further. I know I would do it myself.
(dredmorbius: I am in fact referring to humans. Using microbial life is an interesting idea in its own right however.)
I think if you recognize the advantages and disadvantages of both you could effectively use either of them. Of course doing that might not be considered "humane" by our current standards.
I think the real hope is waiting for hardware to master the "fixing itself" problem (preferably by conquering replication, which would also largely fix the expense problem). Little need to drag along the wetware at that point though.