[AT&T Samsung Galaxy S 5] Bifurcator:
Hi Paul,

The answer to you first question depends what is you want and expect from the launcher. Pretty much all of them are improvements over what the S5 ships with. Most of them offer things like custom folders, multi-select, different wipes, and alternative icon sets. With a few of them I have found that you can install their custom icon sets, then uninstall the launcher and the custom icon remain - so there may be generic custom icon packs which work on any or most launchers - including the default ones your phone came with.

Some of the better launchers embed a video presentation of their launcher in action directly into their play-store download page which is a pretty good way of guessing at whether or not you might wanna try that particular one. If the Launcher's DL page doesn't have a video then YouTube usually does. In my case I used both resources and and watched at lease 30min. of video in total of each before I went for the install action. You can see from the above post which ones I went for after that initial research step. After purchasing and installing six different launchers and all of their associated proprietary widgets & etc. I found the Next 3D Shell Launcher to be the best fit for me. Configured like a wildman it's pretty over the top. I wanted a launcher that had all the bells and whistles AND impressed the heck out of whoever might be looking on - including me. A conversation starter if you will. :) In that regard Next Launcher delivers in spades! My phone is about 2/3 the speed of yours or even slightly less and Next is very smooth on it. But anyway, that's what I wanted out of it - you may have a completely different set of expectations and desires so you need to ask yourself.

Feel free to ask me any questions about any of the ones I listed above. It might take me a few days to see and answer the question but I'll be happy to do so.

On your second question it seems that there is no dependency on a particular ROM by any given Launcher - they all just work. Some require a specific minimum version of Android but the S5 I believe is installed with the very newest Android version so no problems for you there. A few launchers have some functions available only if Root access is available so rooting your S5 might be a consideration if you want or need those functions. The ones I noticed weren't of any significant advantage so I didn't look into rooting my device. And lastly some Launchers have some trouble with some specific phone models. For example there used to be problems with Next on a few of the Samsung phones but that's been addressed already - etc..

One thing to really look into IMO is how much free stuff there is available for the specific launcher and how much requires payment - and I don't really mean icon sets and themes as much as I do custom widgets or tools etc. which are designed to work exclusively with the Launcher in question. If you click on the company name of the developer for the Launcher you're interested in (at the playstore) - that usually calls up a list of items that will tell you what you want to know here.

L8r, again, feel free to ask anything and have fun trying stuff out!