I just came back from Singapore. I was on ANA. I was flying their 787, which has a large business cabin, and surprised by this small section in back of business that had old-looking seats. That was economy plus.
The seats in economy were pretty new with nice vibrant touchscreens that had a usb port and more. The seats in economy plus looked like old-leather seats. Sure, they were bigger, but it didn't seem too different.

Anyway, I've flown by SQ and ANA before (in business and economy): SQ always has good service. This time ANA had grumpy flight attendants. I don't know what upset them, but they weren't as good as Japanese people usually are.

But if you've never flown SQ before, I'd say fly them just for the experience.