Playing these games back to back turned out, for me, to be an interesting open world comparison. 
 
With the bevy of open-world games out there, you sometimes don't know what exactly you're going to get.  Both games turned out to be fun in their own ways, and both had their weak spots too.  Just Case 2 improved vastly on their grapple and parachute systems which is really the draw for this game, they created a new mechanic for travelling in an open world, where nearly any area you can see, you can get to almost immediately.  It makes travelling in small and large spaces quick and easy.  This mechanic was deeply missed going from one open world game to another where traversing the world is a much slower process.  That being said, the shooting and driving and enemy AI aren't as good as they could or should be.   
 
The Saboteur was a nice surprise coming from Just Cause 2.  I was expecting it to not be as good, but it actually was better in a lot of areas.  The first thing that stood out was the level of polish.  The story was much better, I liked the characters and the dialogue, animations were hugely better. The design of the menus and the black and white/colour film noir style of the game also stood out.  But one of the things that impressed me the most about this game was the shooting.  I don't know if I was tainted coming off of the terrible shooting in Just Cause 2, but it felt really good.  I would draw a comparison to Uncharted 2 in the feel of the shooting, with not as good a cover system. The sneaking and disguising mechanics I feel were done well.  Pretty much every mission can be completed with a patient, stealth approach, so if you enjoy playing games that way, it is absolutely an option.  Or you can just go guns blazing.
 
These games have something different to offer, both suffer the inevitable gameplay repetition of most open world games, but both are worth checking out.

The saboteur did have a great shooting... 
That game had a really strange feeling to it that not many other games have given me, cant really explain it but I enjoyed the hell out of the saboteur. 
Also had/s one of the best silenced pistols in games,  walking up to somebody and pulling out that pistol was so damn awesome

 Just Case 2 improved vastly on their grapple and parachute systems which is really the draw for this game, they created a new mechanic for travelling in an open world, where nearly any area you can see, you can get to almost immediately.  It makes travelling in small and large spaces quick and easy.  This mechanic was deeply missed going from one open world game to another where traversing the world is a much slower process. "

But one of the things that impressed me the most about this game was the shooting.  I don't know if I was tainted coming off of the terrible shooting in Just Cause 2, but it felt really good.  "

That game had a really strange feeling to it that not many other games have given me, cant really explain it but I enjoyed the hell out of the saboteur.  

Also had/s one of the best silenced pistols in games,  walking up to somebody and pulling out that pistol was so damn awesome "

" @Ahmad_Metallic: But whilst doing the missions youd be listening to the games awesome soundtrack "

That's kinda crazy, I also hit JC2 and The Saboteur back-to-back.
 
Tho I'm enjoying the setting, story and characters thus far I'm finding The Saboteur too difficult to be entertaining - I think I might be missing something.
 
"...Or you can just go guns blazing" maybe that's it?

Oh right! The Saboteur... can't believe I forgot about that game. Played it a little bit the week I got it, then it was forgotten in the rush of new games. I need to finish this, this game was awesome, and having just played JC2, it seems appropriate. 
 
I feel like the appeal is kinda the same, in the sense that the missions aren't great, but running around and blowing up designated targets is the most fun parts of the game. Just trying to get more coverage on the map. In JC2, I'd love going from one base to another 100% 'em and such, you make money so quickly doing that. Same with Saboteur, just buy a big pack o' dynamite and see how many places you can hit. 

Thanks for the comments guys. 
 
That's right, I forgot to mention both games had great soundtracks.  Just Cause 2 had an impressive orchestral soundtrack.  The Saboteur's didn't stand out as much to me, it was period appropriate for the 1940's setting, but I remember noticing the sound effects were really nice.  The only thing that bugged me were the car radio stations, they only seemed to have like 5 different tracks.

"

Thanks for the comments guys. 
 
That's right, I forgot to mention both games had great soundtracks.  Just Cause 2 had an impressive orchestral soundtrack.  The Saboteur's didn't stand out as much to me, it was period appropriate for the 1940's setting, but I remember noticing the sound effects were really nice.  The only thing that bugged me were the car radio stations, they only seemed to have like 5 different tracks.

"

What I enjoyed most in Saboteur was obtaining the perks. I have yet to play JC2 though

I really disagree with your opinion of the stealth in The Saboteur. Sure, it is possible to do many of the missions with stealth (and I did several this way), but it isn't fun at all. I love the game but that aspect really drags down my opinion of it. My favorite part of the game is its atmosphere. It's hard to explain, but wherever you are on the map, the scenery and mood feels right.

" What I enjoyed most in Saboteur was obtaining the perks. I have yet to play JC2 though "

" I really disagree with your opinion of the stealth in The Saboteur. Sure, it is possible to do many of the missions with stealth (and I did several this way), but it isn't fun at all. "

Very true.  Despite the general critical dislike for Saboteur, it was a very fun game.  I thought the traversal was pretty solid and fun, blowing up the locations was a...blast (sorry), and the Sin-City coloring that morphed into color was beautiful.  I like JC2 more, but The Saboteur was definitely a great swan song for Pandemic.

I also thoroughly enjoyed The Saboteur. I think it was one of the most underrated games of last year, and now you are making me want to start a giant war with nazis on the rooftops of Paris for a few hours now. I wish the game sold better though, it certainly deserved to but I have never tried just cause 2 yet and now I kind of want to buy it.

I loved The Saboteur and it was an amazing send off for Pandemic, although overall it wasn't better than Just Cause 2. I will give The Saboteur credit that when having Nazis in Zepplins, planes, tanks, motorcycles, and jeeps never gets old. I only wish that Just Cause 2 had a better "law enforcement" system in place because I'm really disappointed with the Heat system.

You know what TC? I think you just got me to give The Saboteur a shot. I LOVED Just Cause 2. Among my top 10 of the year.. maybe top 5. But I think I'm ready for the Sab. Also, any comparison to Uncharted 2 is awesome in my book :D