well my 2 cents would be...
First a dumb question: Why would you replace the 777SS with an Excel, did it die?
I have not tried the new ISE models(yet) but from what I have seen of the Excel model, it would be slower than an older model because of its setup. The Excel has both fixed and swivel hammers, and the under cutters as well, so its chewing the garbage down finer than previous models, which will take longer.
I have no explanation as to why it could be so noisy, save for maybe is it mounted correctly? If its not hanging level, the hammers will not be able to balance, and it will vibrate and be noisy.
Today there are basically only 3 companies left that make disposers. ISE, Anaheim, and White Rock. White Rock models are cheapie made in China things under the name of SinkGuard, Dura-Pro, and Monarch.
ISE makes for Sears, Kitchenaid, Maytag, Whirlpool, Emerson, Home Depot(Maintenance Warehouse) and some other private brands.
Anaheim is Waste King, GE, and formerly Sinkmaster and Whirlaway.
I guess if I were to suggest a disposer thats different than the ISE it would be the following one, a Whirlaway. This is Anaheim made, 3/4HP, well made, and powerful. I prefer this over the GE and WK models becuase it has the metal 3-bolt mount instead of the plastic mount of the others. This is a good disposal, I have one that I rotate in now and again. It will eat almost anything(including steak and pork chop bones!) The only downside is its a little louder than an ISE.
I have a youtube video of my Whirlaway in action, I will attach it to the next post.
http://cgi.ebay.com/Garbage-Disposa...ryZ42022QQssPageNameZWDVWQQrdZ1QQcmdZViewItem