Correctomundo...

No audio in, no mp3 playback. If you only use the E60's internal speakers, you are boned, to a certain extent.

But before you make this your primary decision, consider that a small sub mixer is VERY cheap (look at the Rolls ones) and no internal speaker will ever equal even a moderate home stereo system, which you undoubtedly already have...

If you are looking at 76 note arrangers, your choices are very limited, especially those with speakers and low weight and price. You are looking at it, basically. SD-1, PA2Xpro and G70 are MUCH more expensive. Korg and Roland have audio ins (not sure about Ketron, but it and the Korg has an mp3 player, anyway).

And, the best kept secret (until recently, anyway) is that Roland, if you like to edit, create, modify and customize styles and SMF's (something that many do a LOT) is BY FAR the easiest and most powerful on a Roland.

Yes, there's a few features it doesn't have. But there's a boatload of practical day-to-day features that no other arrangers have, either...