Tommy: My initial impressions on the MX-700 are good. It makes setting up one of these remotes a lot easier when you can see right in front of you what is going on. Macros are really easy to create and edit. Even learning is streamlined so that you can learn an entire device in just a few minutes. The only beef I have is that the software is device based, not individual control code based (like the Pronto is.) This led to my initial unhappiness I had the 1st night I had my 700. I could not figure out a way to have all of my receiver's commands, always available. Finally, I ended up duplicating the receiver's codes as a second, hidden device. This solved my troubles and I ended up programming the rest of my stuff with little difficulty.
I've also tinkered enough with the included MX-200 remote to know it makes running one task (like watching TV) MUCH easier (if you have kids or a spouse.) It is capable of issuing complicated macros and yet looks simple.
The MX-500 and MX-700 are the same size and basically the same key layout (although the 700 is just a touch better IMO.) The LCD screens for each is the same with the exception that the 700 has 4 screens per device vs. 2 for the 500. The infrared reach of both seems to be the same. The biggest, and IMO, the most useful difference is that the 700 can do macros till the cows come home. The 500 can only do 15 (still alot for most of us.)
My bottom line is that the 700 is worth the extra money if your macro automation needs exceed the 500 or you need/want PC connectivity (for backups etc.) The MX Editor software isn't there yet (IMO) but they have already released an update. So, I have hope they will work on it to make it all we could hope for.
Hope this helps...