We bought a 150 point Boardwalk resale 4 years ago and have never regretted it. We looked in the 150-200 point range and are very glad we did not go higher than 150 because we also vacation elsewhere.
I see the cost to buy in as a bargain because when we are not at WDW we usually cruise and we have spent that amount in a few cruises--where we have our DVC for the next 30+ years.
We could stay at the values for about a week for what we pay in dues and can get about 12-15 nights in a studio on a year's points.
We are not the typical Disney vacationer. A few years ago we got APs and went to Disney 7 times--there was a promo at the time where you got 15 months on an AP. We bought them on
free dining and did FD again using them. The other times we usually stayed DVC. We got a villa for the in-laws one trip.
We were able to offer points to both our daughters for their honeymooons, but neither used them.
When our passes expired we took 3 weeklong cruises the next year and I went to Vero with friends and kids to use some banked points about to expire. I have more vacation plans than DH gets days

This year we have cruised a couple times and have SeaWorld/Busch Gardens passes so stay at Disney but do not do the parks.
Our points are accumulating! We have never needed to borrow and always bank a majority of points.
Next year we will get Disney waterpark/Disney Quest APs and use a nice pile of accumulated points. We will use them at least 3 times.
We are eager to stay at the villas in California but not at all interested in Aulani--wish soooo much they built on Maui.
We have booked 11 months out but also a month or two out. We love Old Key West and would not be upset if that was all that was available. We love Animal Kingdom and can usually get in there--have used holding points to book this past June and switched a January trip to February a couple years ago.
There is so much flexibility in owning DVC. I love having it and knowing that someday DH and I can spend time golfing there, can take kids and grandkids (none yet) while saving them money, or just spend a week at the beach.
I would never buy direct from Disney. You can save thousands on a resale.
My best advice is as some have said, Start by buying a small amount. It is easier to add on in a few years than sell. I think we would not love DVC as much as we do if we had a ton of points we felt compelled to use.