Whats your opinion here? should I mask the peninsula in the distance so it isnt affected by the gradient filter?

IMO, no. Great photo. I really like the light.

I probably would play with the tones a bit, but it's not the peninsula alone that seems uneven. You have a big, dark circular area in the sky that overlaps the peninsula, much like you get with the use of a CPL. The effect is one of reverse vignetting (brighter corners). The other area you might work on a bit is the very bright patch of water on the left margin, which draws a lot of attention and does not help to keep the eye in the frame (a problem compounded by the leading lines of the foreground rocks, which direct the eye to that bright patch). Otherwise a beautiful scene.

Great scene.
I just have one more small nitpick. There seems to be a dark glow emitting from the front peninsula, as if a feathered burn has been applied to darken the peninsula and it spilled over into the sky.

Very nice. I am not a fan of the yellowish tone, but the compostion, especially the man adding scale to everyting is great!
Cherubino

I agree with Phrasikleia. It does look like some sort of reverse vignetting. Both upper and lower area of the image seem to suffer from this affect. Sort of a concave result in the darkening. You may be able to use the 'Lens Correction' filter in PS to fix this.

What brand of filter were you using? I have experienced this before if I accidently set my Vari-N-Duo filter out of the prescribed range. I make a point to double check to ensure the settings are valid.

Anyway, it's a beautiful composition.

Cheers,
Ed

Looks like it was shot through a window? The colors look odd.

I would mask the near peninsula as the greens and details are clearly darker than the other greens in the photo.

nice scene

@Phrasikleia - thanks I might play with the split toning a little more, the dark patch of sky is more of a concern - I was using a ND filter at dusk, which for some reason made that patch darker (it wasnt set to max)... I might have to bring it to PS to fix that

@mercapto - the darkening around the peninsula (haze) was from a small village behind it, in the evening they light up all the fires... so its actually smoke making its way out to sea.

all in all Im quite happy with what I managed to capture of this beautiful place

First, correct that cyan/green cast. Yes, there may be haloing around the trees. Then select just the peninsula and brighten it a bit.