Although excellent/ideal cuts represent a very small percentage of all diamonds cut and are difficult to find in the average jewelry store, you would have no problem finding one through some of the vendors which participate in this forum.
And faint blue fluorescence has no negative effect on a diamond, in beauty or value.
faint & medium is ok..without a doubt...
strong should be avoided...however, recent studies have suggested
that even with strong blue fluo, you will see very rarely
the oily effect often described before..
Be aware also that a medium blue fluo stone of high color will
sale for less than the same stone without fluo according
to Martin Rapaport..(slight difference).