Don't buy either. The 1020's only benefit is the camera and they're releasing a new 1020 like phone within the next 4 months most likely. The rest of the hardware in the 1020 is far from impressive. The 1520 and 930 camera is not better than the Lumia 1020 camera.. but it IS better than the S5 camera, by quite a margin since the Cyan update! Only to get better with Denim. Remember the Lumia 1020 has a few other drawbacks too, like a really slow camera (amazing pictures, but that thing is SLOW).
The S5 is a phone with a lot of partially functioning gimmicks and Android. It's only a consideration if you REALLY need specific things Android offers over WP8.1 But since 8.1 and 8.1 Update the list is shrinking rapidly. The LG L3 isn't much different from the Samsung S5 honestly, besides having a little less bloatware and a different setup for camera and all. Also the Samsung is a little smaller, which I personally prefer. 5.1" is really the maximum for me. I also prefer the amoled of the samsung over the LG screen. Sure the LG has a lot of pixels, but battery suffers for it a little and the difference between the samsung and LG .. I just couldn't see clearly enough to overcome the benefits of the amoled screen. And you won't notice the difference between 3GB and 2GB of ram. The LG is a phone that fights with specs, where they don't matter all that much for real world performance.
The HTC One M8 For Windows Phone (wtf name) looks OK, but it's also quite a lot more expensive than the 930, while offering very little benefits. If those differences are important enough for you, go for the HTC. But me personally, I hate the HTC design as it's way too geeky, while I love the green 930. Also camera is quite important to me, so that makes the HTC not an option anymore (the camera really is awful compared to Galaxy S5 and Lumia 930).
Like many I was a long time Android user and for some really weird reason I suddenly came home with a Lumia 925. After using that for a while, I just can't go back to Android. But if you're not spoiled by WP yet, your options are still open. I wouldn't hesitate for a second anymore and get a Lumia 930. It obviously offers everything the 1020 does and a lot more. Couple it with a DT-903 with the breathing light and it's the best you can get right now. (http://www.nokia.com/global/products/accessory/dt-903/