actually the intel x25-E is the fastest SSD out
But to answer the OP's question, i'd recommend waiting for a bit and seeing what 256gb SSD Apple is actually using. If you want some of the fastest performance out there and space, i'd go with the Samsung 256gb SSD which just went into production a little while. I recommend waiting because, even though Apple is using Samsung SSD's in its other models, its better not to risk it, and if it doesnt, you should go buy that if you want performance and speed.
http://www.tomshardware.com/news/Samsung-256GB-SSD,6628.html
Check that link for the Read and Write Speeds for the top SSD's out there, and you'll be surprised by the Samsungs numbers for the space they give you![]()
I read various comparisons and I find that on most read speeds the intel x25-m seems to be a bit faster than the x25-e.
But write speeds the x25-e is faster.