What A Friend is certainly interesting for the Grand National. Will run off 156, but has been raised to 171 for the future. Has Aintree form, is a fairly decent sort, and has good ground form in a quickly ran race.
Tidal Bay is probably the classiest horse in the race (on a good day) and wouldn't be surprised to see him staying on at a price.
All depends on the final cut, weights etc.
Last year I went for horses with form over long distances, or on testing ground. The real slogger types that shoulda been staying all day, yet just turned out to be below standard. Only horse I got any money back from was State Of Play placing. Been reading the RP Betting On Horses guide this week just to see what its like as a book. Shame I didn't pick it up a few weeks ago, the Tom Segal festivals section is worth buying on its own.