I have Record on my bike apart from the cassette, which is Chorus. It's basically the same argument; Record has 3 ti cogs, super record has 6 and costs as much as a year's worth of FMBs, and if you're on the big cogs a lot then they will wear out faster than you can ask your bank manager for another loan to buy the next one.
Chorus has an all steel cassette, and lasts and lasts. I'd imagine it's the same for Shimano; stick with Ultegra cassette for longevity.
There is a difference in the number of gears on a common carrier between DA and Ultegra. On an 11-28 the largest 3 gears are on a common carrier for both DA and Ultegra. The DA has the next 2 gears on a common carrier where the Ultegra has separate gears with a spacer between them. Those gears are used a lot and the separate gears can dig into an aluminum hub. Its not just the titanium or lighter weight that makes the DA more expensive.