Probably #3... 1 seems a tad too dark

4

3

3 I'd say

#1 really does it for me!

Something about it just makes the eyes pop in a nice way and it gives the body a lot of depth

3!~ Something about the shading makes the Eevee looks cute!~ nwn

3 and 4 are the best in my eyes but 3 is more my taste

I say #1 looks more realistic, but if you want to go more simple go with #3

i feel like all of them look great, but have different vibes.
1 feels like they are looking at a sunset with their back turned to camera
2 feels like a good one for cuddly situations, or plushie characters
3 feels like its good for more animated cartoon/game characters (and thus is my fav of this eevee drawing :3)
4 feels good for real creatures, or more realistic situations. probably the most versitile imo

(but i dont draw so i could be completely off and take everything i saw with at least 2 grains of salt)

#1 Looks best