Probably one of the best indicators on this is that you will find many on this forum who will only stay at Disney hotels at WDW, but at DLR often prefer a non-Disney hotel.
So here are some kind of random thoughts on the issue...
1. Closer Proximity
When you stay at Disney hotels at WDW you get, among other things, closer proximity to the parks and much better access to the Disney transporation system. IMO this is a huge plus there.
At DLR you do not need to stay at a Disney hotel to be closer to the parks, and there are at least a dozen non-Disney hotels closer to the parks than the DLH and PPH. So at DLR Disney hotels does not necessarily get you closer.
Further, there are many walking distance hotels at DLR and transportation becomes a non-issue if you stay at one of these.
2. More Time Spent Inside The Parks - Less at Hotel
Not sure if everyone is like us in this regard - but I suspect many are - but when we visit DLR we spend a lot more time inside the parks than we do at WDW. Which means we spend less time at the hotel at DLR. So spending extra $$$ for a hotel which you use primarily for sleeping can be viewed as a wasted expense.
When I looked at my trip reports I estimated that at DLR we spend about 11-12 hours per day inside the parks. At WDW I estimated it was more like 7-8 hours.
There are many reasons for this including: many more things to do at WDW outside the parks but still inside WDW, more time wasted on transportation at WDW, DLR has longer park hours and easier parkhopping, better weather overall at DLR and especially in the summer.
3. Magic - DLR Does Not Feel as Immersive
Since DLR is smaller and right it the middle of metropolitan Southern California, the Disney hotels do not not have the same immersive feel as at WDW. It is there at DLR and real, just not as strong.
4. Price - DLR Hotels are Expensive
WDW has Value, Moderate and Deluxe hotels to address a wide range of customer demand and affordability. DLR has only three hotels and they are very pricey compared to the non-Disney hotels - and frankly the value proposition of the DLR hotels is much less convincing than at WDW.
Bottom line...
Most DLR vets are fine staying at non-Disney hotels. We do not feel a serious detraction of the Disney experience at such hotels.
Many are in my camp and are absolutely sold on walking distance hotels at DLR (see "HydroGuy's Hotel Rule"
www.disboards.com/showthread.php?t=1199862). Some are willing to trade-off the walking distance hotel advantage for a nicer hotel (still non-Disney) based on their priorities. Others feel more magic at the DLR Disney hotels are willing to pay for it. The many hotels around DLR offer all of this so folks can choose what suits them best.
HTH
