montunoman,

Answers to your questions:-

1. Does it have the same great sounding Latin styles found on the SD5?
>>> No. The Midijay Plus does.

2. Is it easy to use and connect to a keyboard?
>>> Yes. Via Midi.

3. Could I use a Yamaha psr e413 as a controller?
>>> Yes. If it has the 5pin Midi Out jack.

4. Do you load midi files via thumb drive or the old floppy discs?
>>> Both by USB connected to a PC and Floppy (not thumb drive unless both are connected to a PC).

You will find the Midijay Plus very 'fitting' for your purpose.

Thanks,

AJ