1. I would say that the Realforce is definitely a quality built board. The Filcos are great quality as well but generally come with ABS keycaps as mentioned above.
2. To me the Realforce is it's own animal when it comes to feel and sound. The weight to activate the topres is similar to the reds but that's where it ends. I think the feel is way different. I can type away very quickly with the reds and lightly enough not to bottom out. However, on the topres, I bottom out all the time but it is not a bad feel and doesn't cause any fatigue.
3. I'm not a gamer but use the topres as my daily driver at work. If you are a little bit of a keyboard nut like most on this forum, then yes, the Realforce is worth the money. I currently have two of the silent 87U's. One for at work and another for at home.
4. I am one to try out a multitude of items to find what is the absolute best for me. And usually I can do that with a little bit of research and then settle on the best for me and get rid of the rest. However, with the keyboards in addition to my Realforces, I have a Filco TKL with reds and a Poker with reds. I can say the silent Realforces are my favorites but when I switch at times to the reds, I love them all over again. So I will keep the reds for a change of pace. I also think that the reds are the lightest key
switch out there.
Another thought on the Realforce - I have tried the regular versions and then the silent. I like the silent the best. They are just so quiet and have a wonderful feel. I can only explain the difference - it's like putting your fingers to piano keys. Just soft like butter in feeling and sound. My husband also likes the quiet.
I have tried a few of the Realforces - bought 4 - one full sized, one 86U (both sold) and then the two silent 87U's (keepers).
Go for the Realforce and if you are so inclined go for the silent one - there's nothing like it.