wow. this is like a real life spinal tap. an open e flat sounds no nicer then an open e if it was played a half step up.
Sure there is a difference. Nearly all instruments have different tonal qualities in different tunings. Even within the same tuning, different keys have different tonal qualities due to the resonating frequency of the instrument. To go even further, the same key in the same tuning can have different tonal qualities in different positions (for instance open A major to bar 5 A major). Instruments have a ton of different variables. If you begin to consider harmonic content, it gets even more crazy.
All that aside, a half step up from an E is F. Not E flat.