Hey, I got a pair of costa 400g green mirror sunglasses for Christmas. I'm wondering if I should return them and dish out the extra 50$ for 580g. But if there's not a really noticeable difference then I would like to keep the 400g's. Thanks for any advice you myt have!

If you're happy with them, keep them. 

 

But now that you're going to want more Costa's, get the 580's next time 

I received a pair of the 580p and debated returning the the 580g. I decided to test them out on the water and love them so I kept the 580ps.

I always go with plastic lenses for fishing specific sunglasses due to the safety aspect, so I’d be no help to you here. 

Glass all the way, you will notice a difference.

 

I have Costa 580s and Maui Jims

Out of the two the Maui Jim HD lenses are simply amazing and I now own 2 pair of MJ's

I have been researching glasses over the past few days. What color glass lenses do you guys have? I have been leaning toward green lenses for bright morning fishing.

7 hours ago, Stalking bass said:

I have been researching glasses over the past few days. What color glass lenses do you guys have? I have been leaning toward green lenses for bright morning fishing.

 

I use amber and/or green mirror (amber base) exclusively. Haven’t seen a need for anything else. They work until it’s too dark to need glasses, and they also work in full sun. I don’t fish open water, so I’ve never even tried a pair of blue mirror (gray base). Never been a fan of gray spectrum (gray, black) lenses in sunglasses. I lose too much contrast.

I prefer amber/yellow tint, but my main want is high-contrast and max light transmission.  The old Costa yellow lenses were perfect, but I never managed to find a pair that fit me well before they disappeared. 

I can't speak for the 400's but I can tell you the 580's are well worth the money! I love my amber lens Fantails

I got the 400g and love them only paid $99 well worth every penny!!

I have 400G hamlins in both green and blue mirror. Blue is great for offshore with a lot of glare reflecting off the water. great in saltwater. Green is great for sight fishing, and fishing in shallow water. Id get green but blue looks better.

I have the 580g fantails in green mirror/amber lenses.  They are incredible!  Prior to that I had polarized Oakley's and they don't even compare.  I have not tried the 400 lenses personally, but heard they are a little lighter, which could be better in some ways too.  I think you may get a little better clarity out of the 580, but I don't think it is a huge difference.  The plastic lenses of the 400 are a little more susceptible to scratching, which is the main reason why I went with the 580. 

Doesn’t matter if it’s 580g or 400p they will scratch. The warranty is nice on the frames but don’t be fooled thinking they won’t scratch.