I've been flying in the dark as white against the Scandi when black plays 2...Nf6. I guess it's called the modern version. Anyway, I see an interesting line where you check blacks king with 3.Bb5 then retreat your bishop to protect the extended pawn and then I see most people leaving the poor pawn to die with 3.d4.
Can anyone that knows both lines to some extent offer some idea which way may be more fun or better to play. I'm kind of leaning to 3.Bb5 right now as it looks like it may get more messy.
Thanks.
If you are interested I can give you 1-2 lines which are easy to learn and remember tomorrow.
I have played modern Scandi a lot from the Black side. IMHO 3. d4 is usually the line I find the most testing. Usually Black is happy gambiting a pawn or two in modern Scandi, so I think that if someone was trying really hard to keep the d5 pawn I would probably just ignore it and claim compensation from development.
The line with Bb5+ and Bc4 that you are interested in is a good sequence for white. It does temporarily protect the pawn without falling far behind in development. However, I think that an issue is that after 3. Bb5+ Bd7 4. Bc4 Bg4 white has to choose between f3, which weakens the king, worsens the pawn structure and takes away the f3 square from the knight, or Nf3, which loses the pawn after Nxd5. Although Bc4 is a good attempt at protecting the pawn, I don't think white can win a pawn without giving black compensation.
However, f3 could still be good if you are willing to accept a slightly worse pawn structure and piece activity in exchange for winning the pawn. Stockfish gives +0.5 in this line.
In this line, 5. Nf3 is the most solid choice and after Nxd5, white can castle. In this position, white's king has castled much earlier than black (black will have to focus on moves like e6, Be7 and O-O) and after Nc3 and d4, white has a nice center and better minor pieces. Stockfish gives +0.5 in this line.
Basically, these two continuations are about equal: it all depends on whether you prefer a material advantage or a solid positional advantage.
Of course, 3. c4 is even worse because black can play 3... c6 and if white gets greedy with 4. dxc6, Nxc6 gives black a large lead in development, the possibility of e5, and both the light square bishop and queen are very active. The engine evaluates this line as equal, meaning that white's extra pawn gives no advantage.
Many players play 3. d4 because they would rather not give up a solid positional advantage to protect the pawn, so they waste no time doing so and instead play to control the center. For example, after 3... Nxd5, white can play c4 and create a strong pawn duo on d4 and c4 with the gain of a tempo. This gives white a nice advantage, which Stockfish gives +0.6.
I think that the d4 line is probably stronger than the Bc4 and Nf3 line, so I would suggest that you only play 3. Bb5+ if you really want to protect the pawn on d5.