Hard to say. Both have appeared in tons of comics over the years..
Morrison was pretty good with characterization, and Ostrander did a lot in his series..
I preferred MM under Giffen though. Less of a stick up the rear, and his exchanges with Max Lord were gold. Too bad they ruined all of Max's characterization with recent events..
One thing about DC in general, is how writers tend to ignore foundations laid by previous writers. Ostranders Spectre, Superboy, Cassandra Cain all had great character development. All promptly ignored by the writers who picked up the characters...
Martian Manhunter is kind of in the same boat, being eternally at a loss trying to understand humanity, no matter what lessons he's learned in the past or progress he's made towards finally belonging..
At least Kyle Rayner is an exception. He's gone from a pretty lame replacement to an awesome character...
The three default MM plots:
1) Try and get in touch with humanity
2) Deal with the loss of his species (/be tempted with it's return, possibly in the form of white martians)
3) Try and overcome his weakness to fire
And it's silly because he's really darn connected by now, while the loss of his species will always hurt he's come to grips with it like half a dozen times now, and the fire thing has been lost and come back a few times too.
It's a problem a lot of characters have (did you know that Hank Pym hit his wife several decades ago? Or that Red Tornado found his humanity then blew up?).
Hank Pym beating his wife will hang over him forever.
At this point if you asked someone to describe Hank Pym, wife beater would consistently be up there with incredible genius.
Oh, and don't forget people blaming the creation of Ultron and having a breakdown where he builds a killer robot that he sets to attack his fellow Avengers.
Hank Pym was a troubled man.
A lot of the Avenger's have some dark pasts. Even Hawkeye raped Scarlet Witch for example.