
I think it's fair to say a maximum of six people were surprised that Michael was Ben's "man on the freighter". When you include Harold Perrineau in the opening credits throughout the season it's a bit of a heads-up.
But even with that element of surprise gone, Sarnoff and Vaughan did their best to give us a half-decent recap of Michael's post-island life. And I use the term "life" loosely... he was miserable.
So miserable in fact that after returning to Manhattan he tries unsuccessfully to kill himself. Tom Friendly appears out of the shadows to seize on his desperation, telling him that going undercover on the freighter is his chance to finally earn redemption. Michael reluctantly agrees and boards the freighter under the alias Kevin Johnson. Along the way he meets some familiar folks: Naomi, Minkowski, and Miles to name a few.
Michael's reluctancy settles once he sees Keamy and his mercenaries. Maybe Tom wasn't lying after all, these guys really are dangerous. Unfortunately his cover is blown by Sayid, who drags him into Captain Gault's quarters and spills the beans. And I don't mean the lima beans from the kitchen.
On the island, Ben knows the mercenaries' arrival is impending and thus directs Alex, Danielle, and Karl to head to the Temple. Alex would be the only one to make it back to the barracks alive.
The shock of that final scene aside, I'd say MKJ was slightly above average. It's bookended by several minutes of island time, but 85% of the episode is comprised of Michael's flashbacks in Manhattan and/or scenes on the freighter. It's not quite "LOST Lite" to the extent of early Season 3 but it leans in that direction. Thankfully I care about Michael and wanted to see how his character was evolving — or in this case, regressing.

I've said before that Harold Perrineau was one of the most underrated and underutilized actors on the series, and I'm sticking to it. When I learned this was a Michael-centric I held out hope that we'd get to see a much broader range from Michael, maybe even some happy moments. No such luck, he was still mired in perpetual anguish over his actions on the island.
None of this is a knock on Perrineau's performance in MKJ. He did his usual best with what he was given, and nobody sells a man in his own personal Hell like Perrineau.
If it weren't for Michael Emerson, M.C. Gainey would definitely be my favorite Other. I love Gainey's style of acting, always conveying a subtle mixture of wisdom and sarcasm. It was bizarre seeing him eating fruit in a hotel suite; he's come a long way since "we're gonna have to take the boy."
Bonus points to Tania Raymonde, who was believably horrified by witnessing Karl and Danielle's abrupt death. Raymonde's skills have noticeably improved since her debut in Season 2.

Two moments stood out as directorial highlights:
1. Michael crashing his car into a freight container. Pretty well choreographed, even though one of the angles briefly looks like a mere change in film speed.
2. The final scene with Karl and Danielle getting shot. The scene is set very nicely, giving us a foreboding sense that they'd been surrounding prior to the infamous "water bottle shot".
Bonus points for the CGI of Walt's face in the window at roughly 16:00 in.
Deductions for the very obvious microphone showing in front of Raymonde's right ear before Danielle gets shot. At first I thought it was an earring but in HD it's clearly a mic.

Since I'm a Perrineau fan I honestly don't mind revisiting this episode from time to time, but I admit it feels like a bit of a diversion from the mythology. I'm really not sure how to rank the episode's significance, since his involvement didn't stop Keamy's mercenary team from wreaking havoc. Since one of the rooms was already jam-packed with explosives it would seem the freighter's fate was a foregone conclusion, with or without Michael.

Meet Kevin Johnson was a bit of a disappointment in terms of emotional impact. I was hoping to see Michael get some sort of hope, redemption, purpose. I was hoping for more than Michael being shut out by Walt, still being jerked around by the Others.