53-39T vs. 52-39T

[Miranda]

What's the difference really between these two? Besides the obvious of about one gear inch.

I'm considering switching out my current compact crankset... 50-34T Ultegra Sl & a 12-25 cassette on the back at present.

I'm experiencing the same problem first hand I have read about others having here sometimes... finding a happy spinning gear with the compact. Versus my old ride had a triple 50-39-30T & 12-27 cassette. Used the 30 once. 50 rarely. Mostly all the 39 ring. Well, I think my legs are missing that 39 ring.

So... on the compact, I've ridden the 50 all the time to feel like I'm "getting anywhere". The 34 ring is just frustrating... "getting no where fast" is best I can describe it.

I'm just not sure if the full 53 ring will be too much for me? I didn't even know Shimano made a 52... it's available in my Ultegra sl gruppo.

Does anyone own this? Can you tell the diff? I've never pushed a 53 first hand. I think I could do it. Just don't want it to be too hard on the knees either. Btw, midwest local here... no CO mts to climb or anything.

Just trying to decide what's best?

TYIA.

EDIT ADD: I should also say that there has been a couple times when I have run outta gears with the 50-34T: 1) descending, 2) sprinting standing. FWIW.