Other people have pretty much answered. Bigger and nicer rooms, inside hallways (a real big perk for me) in 90% of the cases balconies (BC I'm looking at you now, get a darn balcony) hot tubs at main pool (which the moderates have as well) but a lot of the deluxe also have them at the small pools. TS restaurants, some don't have QS, mainly the Epcot ones. Maybe a tad nicer grounds. The bus stops are covered, at the values they are not, they are at the moderates as well. They do not have the ques at the bus stops that the values do so it can be a bit of a free for all. The buses are the buses are the buses everywhere.
Some of the deluxe resorts, well maybe all of them, are either within walking distance of some of the parks or have transportation other than buses (only exception might be AKL). WL has a boat to MK. CR and GF you can walk, boat or monorail to MK. Poly you can monorail, take a boat or walk if you really are tough to MK. All three of those also have monorail to Epcot, unless the monorail is down, that is the only way you can get to Epcot from them. BW, BC and YC have boats to both Epcot and HS and you can also walk to both of those parks. Riv has the sky liner to Epcot. Riv is technically not a deluxe as it is a DVC with no resort attached, which all the others on property have. You can book rooms for cash there but it is a DVC resort.
The value resorts are motels, the moderates are as well but maybe a tad more upscale. They can be very loud and crowded.
Is it worth the money to go from value to deluxe? It really is up to your finances, your style of doing Disney and if you spend a lot of time at the resort. Before I started staying at values and moderates, I would take a few hours out of each day and go tour the other resorts, just to see what was what since I had never actually stepped foot in them. I have now stayed in just about every property on site even the in our RV at the campground and at Shades of Green before it was military. The only places I have not stayed: SS, WL, AoA (and I don't see me staying there unless I need a suite) ASMu and Riv.