Is the Benko Gambit good for black

Kasparov and a few others have regularly used the Benko Gambit with the black pieces, but most chess players will probably opt for a non-gambit opening or something more solid objectively speaking. The Benko isn't bad (I actually like it a lot), but I have my doubts about how objectively sound it is (but then again, I question this to almost every gambit opening). 

Probably the biggest problem with playing the black side of the Benko Gambit by repertoire is that your opponent won't play into it that often and so your repertoire with the black pieces will need to include a lot of supplementing variations - probably some Benoni mainlines or maybe some 1...Nf6 lines if that is your chosen move order (Benko Gambit can also begin from other move orders like the Old Benoni with 1. d4 c5 2. d5).

One thing I do love about the Benko Gambit is that black seems to have compensation even if the Queens are exchanged. Most gambit openings sacrifice material and trading pieces off (especially Queens) dissipates the attack or initiative, so the fact that this isn't really true in the Benko Gambit, I do like for black. 

However, I still have my doubts about how sound this opening is with the black pieces. It is a strong opening I respect and it has plenty of theory and ideas to learn which makes it practical for players under "expert level" but at the higher levels, I don't think this opening is common for a reason. Yes, I realize that some strong players use this opening (I mentioned Kasparov, but I also think Topalov and Shirov used it for some games as well), but they can play pretty much anything with good success given their high chess ability.

If we setup two engines with "perfect play" (or near enough to perfect with the technology we have) and setup the mainline Benko Gambit...I predict that white will score better, but this is just my intuition from studying the opening (for both sides) myself and my limited experience with this opening.

Er . . . the Marshall?

That one looks a lot sounder than the Benko these days (fond though I am of the latter). 

@1

"Is the Benko Gambit good for black"
++ It is more or less sound. Kasparov has played it, but not in high level games.

A) At the master level, a draw means Black has done well. 
B) Even at the master level, the Marshall is only a draw 40% of the time.  That’s nowhere near 100%.

C) Yes, there are fewer draws in the Benko — but only because Black loses more often.

D) At the club level both are entirely playable (though the Benko is tough if you run into someone who’s learned the critical 12 a4 line), and neither is particularly likely to result in a draw.

At your level, you should play a simpler opening, that is if you want to learn the modern variation that comes with a lot but a lot of sidelines, and have engrained lot of tactics patterns and it requires good calculation skills.

You should focus on studying on other subjects  rather than openings, now if you really insist on playing the Benko and putting the time to learn everything, yes it's playable, very sharp usually White crumbles, you also need a mindset that just go for the kill  if you manage to win the pawns back you are playing for the win since your pawns are all in a pawn island.

Also I recommend playing the Kasparov Gambit 1.d4 Nf6 2.c4 c5 3.Nf3 cxd4 4.Nxd4 e5, most people don't know how to follow up and it's fairly good for black.

in blitz I find it works