MTG Salvation

As the title states is it worth buying in now or just to wait until May?

Well you can aquire a few black cards like Hero's Downfall and especially Thoughtseize.
They will certainly show up in decks for the entire time there are standard legal.

I agree and prices on Thoughseize and Hero's Downfall are likely to rise. If you know what colors you like to play the scry lands are a good investment.

The scry lands are probably a good investment in general. Good one drops are another thing that will be fine.

The best time is just before the next set. People stop buying and start watching out for the spoilers and saving money to get their hands on the brand new cards. furthermore people tend to get bored with a stale standard by that time.

Well you can go ahead and buy Theros but I would suggest just waiting until rotation to buy back in fully.