Wow 3 people stating they liked the 55g better, now I am curious... The only topre I have tried is my HHKB which is 45g, I honestly feel they are perfect as far as weight.. I prefer lighter switches since my joints in my fingers always kill due to long hours on the computer, but I wonder how light the 55 actually feels. Personally if/when I get a realforce I think 45g would be perfect, but again thats without trying a 55g. Isn't the variable switch model made mostly of 45g switches?
I can relate to the sore knuckles. I had been using a Das Ultimate with browns for 2.5 years. At the end of a long day at my keyboard, my knuckles ached. I mean some days it was downright painful. That's the primary reason I tried Topre. I'm 55 and have been banging on keyboards for 30 years. In addition, I spent 27 years in martial arts, so I've sprained my finger joints so many times I couldn't begin to count. When you get older, those past sports injuries tend to rear their ugly head.
Last October, I bought RF 87U variable silent. So, 30g and 45g. I can tell you the difference in joint pain is astounding. In fact, there isn't any. On the Cherry browns, it was daily.
I've also been using my new HHKB Pro 2 that came yesterday. The key feel between the two is slightly different. But I'll comment on key weighting.
The all 45g HHKB is pure Topre heaven. And it wouldn't require much adjustment in your typing style if you're coming from Cherry browns for example.
When I first got the variable 30g - 45g RF, I was coming from browns. I found myself pounding the keys on the RF. So I made a conscious effort to lighten up my style. Of course, this required a more relaxed attack on the keys. I found myself being much more relaxed in front of the keyboard. Less 'deliberate' maybe? It took a good week to establish a lighter typing style without having to continually catch myself typing too heavily. But now that I've adjusted to the lighter, more relaxed typing style, I really like it. I've never had the pleasure of using a all 45g or 55g RF. Most guys seem to prefer those. And if I get another RF, I may give the 45g a try.
So...if you go with the all 45g or 55g, you will probably have less joint pain and not have to change your typing style much. If you go the variable, be prepared to make some changes to your typing style. The real question is to ask yourself is...will you prefer the lighter typing style? Either way, you will have less joint pain coming from Cherry MX.
Hope that helps...