By my signature you can see I've been to WDW many times. We just got back from a 3 week trip to Europe which concluded with 3 days at DLP.
There are many great things about DLP that you can't get at the American Parks:
The incredible beauty and theming of Disneyland Paris
Adventure Isle is awesome
Some rides are better, and others are different but just as excellent as their American cousins
Disney Dreams was one of the best nighttime shows I've ever seen
We all loved the Magic Everywhere Parade
Everything is within walking distance of everything else
The castle is awesome, especially with the walk-through and dragon
That being said, there are some things about DLP that we thought were big downgrades from WDW. Some were minor, like the theming at the resorts isn't as detailed as many of the WDW resorts (ie. comparing WL to SL, or BC to NBH) The biggest negative difference is that DLP seems VERY, VERY understaffed. I believe this is where the much of the perceived "lack of magic" stems from.
Garbage cans were overflowing, and we rarely saw a CM out cleaning up or emptying them.
When you have a problem, such as the FP machines not working, or to ask for directions, it is difficult to find a CM to help you. When you do, you are likely interrupting them from doing something else. Rarely is there someone staffed who's job it is just to help you.
There are no CM's giving high-fives with Mickey hands, handing out stickers, or just hanging around to wish you a magical day.
Before parades and shows (and at other times like when the parks open) there are no CM's doing crowd control, so the crowds tend to get out-of-control.
Due to lack of CMs, lack of enforcement, or both, guests seem to ignore any rules that are in place in the park, including smoking only in designated areas, staying out of gated areas, lawns, flowerbeds, and fountains.
Even though the theming is incredible, the upkeep in the parks is woefully lacking. Many handrails are stripped down to the metal, guests have carved their names into many walls and other surfaces, and ride breakdowns are very common.
We did meet a higher percentage of rude CMs than at WDW (mostly revolving around pin trading), but we also met a few exceptional CMs as we do on each trip to WDW.
In a nutshell, we enjoyed our time at DLP and as Disney Park fans we're glad we went, but I don't see a return trip anytime in the near future.
Hope that helped. I tried to be as objective as possible.
You can see our trip report here:
http://www.disboards.com/showthread.php?t=2980770