Hi, daratwist. Franke Orca owner here. The Elkay looks like a nice sink - I never looked at it before, but I can point out a few things to consider:
1) The faucet mount on this sink is all the way on the left, while the Orca's is in the middle. I like the faucet placement of the Orca better because the faucet can swing to reach all parts of the sink.
2) The drain looks to be in the front, the Orca's is in the back. Not sure if this is better or worse, just different. I think I prefer back because I put my dirty pots down in the front and they don't block the drain.
3) the shelf on the right is very close to the bottom of the sink. I use my right shelf all the time, and I don't think I'd like reaching under there to sweep stuff out. Plus, even if using a sprayer to clear it, the shelf grid looks like it would block a lot of the spray and possibly splash it back.
4) depth - this sink is shallower, as you mentioned. I personally love having a deep sink. I don't have a filtration system so I can't comment on that.
5) this sink is slightly wider than the Orca. The Orca can fit in a 33" base cabinet while this one requires a 36". I needed the 3", you may not.

Good luck!

I looked at both of these too. I ended up with the Orca, my water was just hooked up last night and I LOVE it!

I only have a 33 in cabinet, so that was a big part of my decision. The Mistic says 36 in min cabinet. I also did not want my faucet at one end, especially the left end since I'm right handed.

To me, they look to function very similar in that they are both relatively deep, have an integrated shelf ledge, and large interior space. I'd think you would be happy with either.

I had a bunch of stuff to wash last night before putting it away. We do have the bottom and right side grids for the Orca. I set up a tub of water on the right grid and literally filled the sink with stuff. The grid put the tub of water at a great height for me, and the bottom grid was also comfortable. I could wash and return stuff to the sink, then just rinse as I moved to the drying area. Once I was done, I could put stuff on the bottom, right grid, and colander accessory to have 3 tiers drying plus keep the tub and a large colander draining in the left side area.

So to answer your question about comparing, the differences I weighed were
-all one width vs two widths
-faucet placement
-depth
-minimum cabinet size needed
-cost
-one side with shelf vs two sides with shelf available

Both are much better than my shallow double sink in terms of functionality. And quite honestly, by the time I hit week 5 with no sink, I would have been thrilled with any of the sinks I looked at seriously. But I was actually smiling doing the dishes in the Orca last night, and I hate doing dishes.

Thanks so much for your comments. It is very helpful. I hadn't thought too much about the drain being forward and the faucet reach is very important. I think I will buy the Orca.

I chose the Franke Orca myself and just had it installed one month ago. I absolutely love it. I did not want to waste a larger cabinet size for the sink base when i could use a larger base cabinet to the left. Also, I did not like the look of the grid on the Elkay. They do not look as refined even if they are just as expensive. I love the depth of the sink and have no problem with room under the sink for the garbage disposal, etc. Another consideration was the placement of the faucet. My sink is under a decent sized but not huge window and so even though the Orca is a bit offset, the faucet is still centered under my window. It is a beautiful sink and the quality is reflected.

Another Orca owner here. Ditto to all the advantages listed above. At 2 years, love my sink, and it still looks like new. May I recommend Kitchen & Bath Authority, esp. one of their combo packages? Great prices and top quality business practices. I saved some money with one of their Franke combo packs (Orca sink, two grids, faucet, soap dispenser & also negotiated a price on the Franke air switch). Very happy with all products, top quality that should last for many years.