And I figured out the answer to my question...sort of. After reading about MFAA
http://www.hardocp.com/article/2014/11/25/nvidia_multiframe_sampled_aa_video_card_review/1 and it's predecessor, CSAA
http://www.hardocp.com/article/2006/11/08/bfgtech_geforce_8800_gtx_gts/7#.VWx51s-qpBf I understood some things, especially after testing.
For anyone else wondering about MY QUESTION, this is what I've found out:
FXAA - both minor performance & quality impact (the blurring method it uses is imperceivable unless you're really hunting for it);
MFAA - supposedly 2x better performance than any MSAA options used IN GAME (ex.: 2xMFAA offers 4xMSAA quality, 4xMFAA offers 8xMSAA) + the game has to support this function, which right now, few do (see link for more details);
SSAA 8x - in
NVIDIA Control Panel(NVCP) ->
Antialiasing - Transparency ->
8x SuperSample for maximum quality with a big hit on performance therefore it's advisable to try MultiSample, 2x and 4x as well and if all fail to deliver good performance, then Off it.
MSAA - 1) If game has built in AA setting, choose one,make sure to Apply and save it, then quit game and go to:
NVCP-> Antialiasing - Mode ->
Enhance the application setting, then
Antialiasing - Setting and choose 2x, 4x, 8x. It will OVERRIDE the IN GAME chosen setting, so it doesn't matter what you choose, unless it comforts you to have all on max;
- 2) If game has no built in AA setting,
NVCP ->
Antialiasing - Mode ->
Override any application setting, then same as above, choose 2x, 4x, 8x.
From what I understand, this is overkill "brute" quality AA thus being a massive hit to performance, even tho' is covering only external polygons, at least it's the best option because it doesn't blur...if you have the headroom for it, of course.
TXAA - Medium to high performance impact for heavy blur AA quality which, honestly, isn't easy on the eyes and makes the game look...washed. It's proprietary to NVIDIA and I'd recommend using it, ONLY if all other options fail at removing jaggies, if not, it's best left alone because the AA quality it offers is greatly outbalanced by the bluriness. Can be found in most NVIDIA - Meant to be played games, AA setting.
SMAA - Never encountered this so I can't speak about it for now.
I'd advise, in general, at keeping
FXAA and
MFAA on (unless you really need performance, then you can play with them to get the desired effect) and
Antialiasing - Mode -> Application controlled (unless you really have a jaggie problem and the headroom to deal with the "brute" MSAA) and
Antialiasing - Transparency SSAA 8x (unless fishing for performance) and then just drop it according to each game that requires more "juice".
I've made this post in search of an enlightening answer for the best AntiAliasing solution out there (quality with as less blur and performance hit as possible), but for once, Google couldn't help me, so after some deep research I hope that whoever will have similar questions, can find an answer here. 
Also, please, someone make this a sticky and by all means, add to it (especially on the SMAA front) with knowledge made easy for everyone to understand.