Berlin Defence or Petroff?

Which one is harder to beat?

Berlin. I don't play either though, but that's my opinion, there are actually many sharp lines in the petroff despite it's drawish reputation.

Given that it says "Which one is harder to beat?", and we are talking Defenses, not Attacks, that would imply that they are asking which is harder for White to beat.

I would have to say the Berlin is probably harder to beat than the Petroff, but the Berlin also probably has a lower win ratio for Black, though I have won with it many times.

Which one has a lower win percentage for white?

Ask Kasparov  ;)

Played the Petroff for a while, but mostly ended up defending the black side of the Four Knights, and occasional Cochranes.

Played the Berlin for a while, but mostly ended up defending the black side of the Spanish Four Knights, and occasional Nf6 Exchanges.

In my experience, players club level and below simply don't play either of these lines if they can help it.  And they can.

There is no magic bullet opening. What kind of middlegame do you want to play over and over again?

I had intended to pick up the petroff after a recent tournament.
However, at the tournament i stumbled upon a book on the Berlin and I recalled some quotes from this forum on how learning the ruy lopez is important for progress. Also some thoughts from Pfren and others on how rich the endgames in the Berlin are.

I decided to first learn the Berlin, in this time I would not only be learning alo how to deal with the open games ex/italian, KG etc but also improving my endgame skill. By this method I believe if I decide eventually that I enjoy the petroff more, learning the black side of the spanish and the Berlin in particular will have made me a better petroff player.

I would dislike facing the Petrov Defense more.  If someone plays the Ruy Lopez against you he or she would likely be prepared to face the Berlin.  Personally, I would feel a bit more out of my element countering the Petrov.  That said, I would pick the one that leads to the type of play you prefer. I defend e4 almost exclusively with the sicilian so I can't really vouch for how it feels to play them, just how it feels to attack it.  A plus side about the Petrov is you can sidestep the Ruy Lopez and Scotch game, so if you don't like facing those that's something to consider.  On the minus side the Petrov feels a bit dull, but that's just an opinion.

I do not think that is so true.

I played 1.e4 for a short while (just for some 'fresh air') and had intended to have some fun with the ruy. The petroff came up much more often against me than the 2..nc6 did.

I simply believe this is because there is so much white can try to avoid your pet spanish variation, the d3 spanish lines, all the open games, the exchange ruy..and after all this you still need to deal with the people who play the mainlines!.

By contrast the petroff begins on move 2. It is quite forcing and the alternative to nxe5, the four knights is not so challenging for black. Its solid and requires much less preparation. This is the reason I believe it is more popular at club/low tournament level.

In this way I believe someone following the mainline of the Berlin would come as much more of a 'surprise' as someone playing the petroff, and may even have them racking their brain trying to remember the complicated middle/end game plans they only get to use once in a blue moon.

Once again, on the flipside. Te petroff is much easier to master, so you will not suffer at the hands of someone who does play it often, so either way..

I don't know the allure of these two openings. I have gotten pretty good play with the Breyer Variation for some decades now.

What allures me to them is:

Berlin: very rich, instructive and fun endgames

Petroff: Relatively easy play, very solid.

IMO the Petroff is harder to beat. The Berlin endgame can be sidestepped by 4.d3 and c3 later. I have bad records against the Petroff.

4.d3?! Ne7!? and black is equal

The most important thing in choosing openings is to have a comfortable middle game positions su bject to one's taste. It does not matter if black equalizes according to theory.

Straight out of Cox's Berlin Wall...

...4.d3 is a move to take very seriously.  Kasparov openly regretted not trying it in 2000, while Kramnik says on his DVD that it is a dangerous move, and that he and his team already knew this in 2000 and had to work long and hard to find a way to try and equalise.  Indeed Kramnik lost four consecutive games against it in 2005.

If only Kramnik had thought, "hey, I know, ...4e7! equalizes on the spot," he could have saved himself a lot of trouble.

But I guess that only says it's difficult at the 2800+ level.  For the bridge and tunnel crowd, it's probably a cakewalk.

Berlin probably.Its not called Berlin Wall for no reason

The Cox book, by the way, is one of the best reasons to consider the Berlin.  The first 150 pages of the book are split half into typical endgame considerations, and half into typical positional and tactical motifs.

Second half of the book is all theory, but not many writers give you that depth of clubber-friendly tutelage in an opening monograph.