Recently flew EK F (JFK - DXB) and LHR - SIN (SQ R) and here's a brief comparison:

Hard product
EK wins hands down. The EK F Suites offer by far more privacy, have a mini-bar where you can store your preferred beverages, and I love being able to take a shower (A380 only) before going to sleep on a plane. The vanity area is also a nice feature.

My big criticisms of SQ R remain the flimsy doors which can rock back and forth and the shades of the internal Suite windows have an opening at the bottom that allows light from neighboring Suites to get in. Also, I hope that SQ considers upgrading the R product with materials that do not look like cheap plastic and more closely resemble the new F 77W materials.

Amenities
I'm not a fan of the EK F amenity kit and pajamas, especially the latter, which isn't really of good material in my opinion. On the other hand, I find the SQ F/R amenity kit and pajamas to be excellent. I even use my SQ R/F pajamas to work out sometimes. Further, I am a big fan of SQ's bedding. EK's bedding isn't bad, but it doesn't have the rich feeling of SQ's.

Cabin Crew
I had fantastic crews on both airlines, yet SQ is the winner in this category since the Leading Stewardess looking after me could not have been more gracious. Her service was flawless throughout the flight. She even noticed I was reading Pride and Prejudice and she asked me whether I had gotten to the part where Lady Catherine confronts Elizabeth. I was truly impressed, but then again, SQ's cabin crews tend to be very intelligent.

Inflight Entertainment
Both EK and SQ have excellent IFE. EK's ICE, however, is more comprehensible so it gets my vote.

Meals
EK provided great, though certainly not excellent meals. My beef had a funny taste.

SQ meals were significantly worse. My Book the Cook corn fed chicken entree was very dry and I couldn't eat it. The lovely cabin crew couldn't have been more gracious and apologetic offering alternatives, which were appreciated, but nevertheless almost inedible as well. To the cabin crew's credit, they brought me additional caviar once they realized I still wasn't eating much of the second entree, not to mention many, many delicious cups of hot chocolate made from the heart.

Conclusion
Based on these two trips, I'd give EK F an overall rating of 94/100 and SQ R 91/100. In terms of value, I do strongly believe that EK F is the real winner, as SQ has a tendency to overprice its R product.

I'm gonna be out on a cruise for a few days, but let me know if you guys have any questions.