My 15g tank is a couple of years old but I ended up taking the protein skimmer out after using it for more than a year and switching it out for the Marina S15 Power Filter - the tank is so close to the wall that this really narrow filter fits like a dream.
Protein skimmers seem to be a mixture of personal choice and end goal. I loved how my skimmer added additional oxygenation to the water, helping to bump up the PH, but I adjusted my wave maker to help with that after I removed it. It definitely pulled out the nasties in a decent goopy skim, but I wanted to try something different.
So far I like the change, and my husband likes that the faint high pitched gurgling noises no longer sound like we have a happy treefrog chirping in our kitchen. (It wasn't really loud, just something you noticed at times)
I think the skimmer helped with filtration for my young tank, and now that it's more well-established, I could take it out since my bioload isn't too high.
All of that being said, if you're already planning to switch out for the Tidal 35, I'd start with that, no protein skimmer, and then see how your tank progresses. Know that you will have to rinse out sponges or media with fair regularity as they can become a nutrient trap. The Tidal 35 also looks like it has a surface skimmer built in, which you will really like - I had to add a separate surface skimmer to my set up.