Kings Gambit: 3. Nf3 or 3. Bc4?

Hi, I recently started to play the kings gambit (REALLY fun opening) in super casual blitz games and was wondering what people in general think whites best third move is. I've read the phrase "Nf3 for a draw, Bc4 for a win" before, and wanted to get more opinions on which is more effective.

Also, why is Bc4 considered more aggressive? Is it worth losing castling rights? Given the opportunity, is it usually better to eventually sac my f3 knight or my light squared bishop on f7 when trying to stop their king from castling and open up the f file (I know it changes depending on the circumstance, just wondering which piece is usually more valuable)? Is the kings gambit sound enough to use in lower level rapid games? 

Thanks in advance.

You have a Diamond membership. Therefore you have access to Simon Williams' videos on the KG. Now, he's Simon Williams, and therefore everything he says should be taken with a grain of salt. But still, watch them. Then you'll have some idea. He discusses both options.

To be completely objective, rather than "Nf3 for a draw, Bc4 for a win", it's more like "Nf3 - Black plays for a win, Bc4 - White may be okay", but 3 Nf3 leads to more interesting games.

I think the problem with your question is it is all a matter of perspective and really, you never going to get an answer that is going to be fully right or wrong.

The two answers I like so far are that of Urk and NM Jatait. Urk correctly points out that depending on the circumstance you are trying the King's Gambit as an opening, the more likelyhood you are having some success out of the opening. However on the other hand the NM is also quite right in the respect, at his level (and because of that from his perspective) the King's Gambit might not work as well.

As for myself, I play the King's Gambit. Even in this digital age where most players over a certain rating are PROBABLY armed to the teeth with chess engines, I even play it in correspondence....why?....You plug 1.e4 e5 2.f4 exf4 and most engines (but not all) will tell you Black has an advanatge of some kind and as the opening progresses this assessment by the digital demon really changes much if all.....that is, until the Blacks pawn on f4 falls off and 9 times out of 10 the assessment swings 180 degrees into Whites favor, if only slightly.

But I am sure someone out there will tell me I am wrong....as i said its all perspective.

I actually play the King's Gambit from both sides

Checking my record (OTB at standard time limits) over recent years:
White: P24, W17, D6, L1 — 83.3%
Black: P10, W7, D3, L0 — 85%

To summarize that: I win as White because my opponents don't really know what they're doing. I win as Black because I do know what I'm doing.

My advice for White would be to avoid the theoretical main lines. The King's Gambit is primarily an improvisors' opening. So look for slightly offbeat ideas that will force your opponents to think for themselves as soon as possible.

For Black, don't bother about other people's recommendations either. In my opinion, all defences to the King's Gambit are good, so pick one you like the look of and make it your pet line.

My own choices: as White I often play 3 Nc3!?, and as Black 3 Nf3 h5!? and 3 Bc4 f5!?. My record with such variations is as above.

John Shaw in his King's Gambit book (2013) claims that 3. Bc4 is refuted by the reply 3...Nc6.

John Shaw is mistaken there.

3.Nf3 h5 is a real line?

Ok. Does http://www.chesspub.com/cgi-bin/chess/YaBB.pl?num=1224328419/143 hold the answer considering you posted in there?

Yes, it's the Wagenbach Defence

See here: http://200opengames.blogspot.co.uk/2016/09/001-playing-that-rubbish.html

That's possibly one answer, yes – as I tested in a game posted in that thread: http://www.chesspub.com/cgi-bin/chess/YaBB.pl?num=1224328419/143#143

It's not a great position for White or anything, but it seems more or less okay.

Just to clarify: the Falkbeer is 2...d5 3 exd5 e4, which is really not very good at all, though Black may still be able to defend if very well prepared.

As for 2...exf4 3 Nf3 d5 – if that's what you mean – there's no reason for White to avoid that line in particular. Black is perfectly okay of course, but giving a pawn back is far less testing to White's opening than many of Black's other defences.

In any case 3 Bc4 doesn't avoid it. Black can still play 3...d5 here. Or indeed 2...d5 3 exd5 exf4 and so on.

No, I'm happy with the obscure positions after 1 e4 e5 2 f4 Nc6 3 Nf3 f5. But of course 2...exf4 3 Nc3 and then 3...Nc6 transposes to the Vienna Gambit lines, such as the Steinitz (4 d4) or Hamppe-Allgaier (4 Nf3 g5 5 h4)

There is nothing wrong with playing 3 ... Qh4+ in the 3. Bc4 systems. Black gets perfectly fine play as is shown by both Bologan and Ntrilis in their e5 books

I am intrigued by this. I used to be quite the Mason (Keres) Gambit fan. I even played it in correspondence. However it was 8 years ago, in 2009 against a player 519 ELO less than me I was presented with 1.e4 e5 2.f4 exf4 3.Nc3 Qh4+ 4.Ke2 Ne7!? Which I had at the time, never seen before. Cutting a long story short, I never managed to get either my pawn back or any decent play for it and I only won the game when my opponent defaulted. I still believe that 4…Ne7!? Is close to a refutation of Mason Gambit. Has it been repaired?

As an aside. I managed to lay my hands on a copy of “Das angenommene Konigsgambit mit 3.Sc3” by Bangiev and Herget. A good book in that it is quite thorough. Mind you while it is that, I did manage to find one mistake... 

but follow one of these lines on

i like more nf3

Some good analysis I read years ago tells us that with 3.Nf3, white's real chances to win are to win in the ending, where white is better.