Mello Roos are def a big con 1.4-1.9% taxish. I would just run the math and then add on the cost of it to the house when comparing houses. Probably +70K ish to the house price (this will very just run the numbers).
As for stores nearby I would disagree with the above comment.
As of now nothing is really walk able store wise (town-center is coming with rumored Target and Trader Joes but that is not set in stone as far as I know).
But the nearby 4S strip mall has a ton of stuff. I would say its about 1.5 miles and a 4 minute drive. Multiple restaurants (10ish, 3 sitdowns and 7 or so upscale fast food), grocery stores, library, ace hardware. Then there are two more areas with a bunch of stores and restaurants within 7 minutes.
Then there is a whole bunch of stores and restaurants including Costco, Home Depot and a movie theater at Carmel Mt (5 ish miles away, 12 minutes).
Basically it is a bunch of places that appeal to a 30-50 year old. Most places are kind of upscale chains in between fast food and pure sit down. Nothing really super cool that has been around for a long time but plenty of variety/convenient places.
There are three directions out of Del Sur. To the South it is about 8 miles and 12 minutes to the 56, to the East it is about 3.5 miles and 7 minutes to the 15 and taking San Diegeto rd West is about 20 minutes to Del Mar race track.