I think this really highlights that there is no "right" answer to onsite vs. offsite. It very much depends on your own personal preferences.
Some people don't want to have to drive while at Disney. Others can't stand taking buses.
Some don't want to cook their own meals. Others can't stand eating out 3 meals a day.
Some want a maid to come in and clean and make the beds every day. Others hate having a stranger come in and touch their stuff.
Some want to be surrounded by Disney 24/7. Others want an escape from the Disney bubble at the end of the day.
Both groups are "right" because it is what they prefer. The great thing about traveling to Disney World is that there are endless options with something to fit everyone's preferences.
An excellent, balanced, summary. Far too many posters, not really in this thread, can't imagine a person having an opposing opinion.
This is an onsite perk that often gets overlooked. When staying onsite, your whole party doesn't have to travel as one group. They can easily split up. The teens can sleep in and meet up with the family later in the day. Or mom can take the toddler back to the room for a nap while dad stays in the park with the older kid. Or mom, dad, and the kids can go to the waterpark for the day while grandmom and grandpop do some shopping at DTD or catch a movie.
And let's not forget that staying onsite you can enjoy an adult beverage or two and not have to worry about driving back to your offsite accommodations. Last year we stayed onsite for the first time in about 15 years because we won a trip from the DIS! We spent 3 days at the Swan and the one evening we walked into Epcot (also something you can't do from offsite), I stopped at the kiosk in France and bought one of those Grey Goose orange slushie drinks. I can't tell you the last time I had alcohol at Disney because I'm always the one driving and I will not drink and drive. I'm not a big drinker (especially at Disney prices) but it was nice to be able to do it and not worry about getting home.
Very much overlooked. A great point.
Another offsite convenience is parking. At most places we've rented, you park right outside your rental unit, sometimes literally a few feet from the door, or even in the garage of your rental home. Onsite, you usually have to park quite a ways from where you are actually staying.
Not really an issue if you plan on using Disney transportation most of the time. A complete non-issue if you plan on skipping a car.
Post a question like this on the resort boards posters will tell you staying offsite loses the Disney magic........
Post the question in this board and people talk about space and $$$$
Frequently the "right" answer (for the OP) is obvious from the way the question is asked.
Examples
I generally stay in a vacation home., Will I miss the XXX square footage, washer dryer, private pool etc? Will my family of 5 be happy in one room in All Stars. NO.
My husband drivers 100K per year for work. His favorite aspect of our WDW vacation is not driving. Will he be happy offsite. NO.
Afternoon break. A thought. The "better" the accommodations the less likely you'll want to go back.A nice offsite condo offers reasons to stay. A family of 4, 2 rooms in a deluxe (or moderate) Might want to enjoy the pool, dining etc. Family of 4 in one room in a value resort. How fast can you get back on a bus to a theme park.
How many times have the family been to Disney? How long until their next trip? Posters on DIS aren't the norm. A number of years I read the average Disney family makes one (or two) trips in their lifetime. They don't care how much credit card debt they incur.
I have no doubt DVC owners take more trips.
The more times I've been to Disney the less concerned I am about missing an attraction. A family who isn't planning a quick return is going to want to maximize park time. EMH becomes more important. Afternoon rest time less important. Using DME and skipping a rental car makes sense.
I don't like FP+. I have little doubt the next round of "tinkering" will favor onsite guests even more then the present system.
edited to add:
Offsite is almost always very inconvenient if you skip the rental car. Offsite shuttles tend to be poor. DTD hotels are the exception, but aren't they technically on Disney property.