I have two 87Us in variable silent, an HHKB Pro 2 (non silent) and an 87U 55g. I like them all, but for different tasks.
The 55g has a nice snappy feel and is great for coding where you're typing in short bursts. More tactile than the other Topre switches. However, for extended typing sessions - as a writer would - it's a bit too heavy for me. I honestly don't feel much difference between the 45g switches and the variable, but the 55g is definitely different. You wouldn't think 10g would make that much of a difference, but it does for me. Your typing style with be the defining factor here. If you are a deliberate, aggressive typist, you will like the 55g. If you're a more relaxed typist, it will be tiring by the end of the day.
The HHKB is an interesting subject. One would think the Fn layer would slow you down in terms of text navigation with the arrow and F keys, pg up, pg down, home and end keys. However, if you stick with it, it *can* actually be faster for text navigation because your fingers don't have to leave home row.
But the HHKB's form factor falls a tad short for me. I rely upon both Win keys, which is the mainstay for keyboard shortcuts in Win 8.1, and even more so in Win 10. The reason it falls short is because for the left Win key, I have to designate that as either a Win key OR a Fn key via a dip switch. If I designate it a Win key, I've got my keyboard shortcuts, but F6 - F12 are the a pain in the butt because you're actuating the Fn key with your right pinky finger. That's a big stretch to accomplish with your right hand. To designate the left Win key as a Fn key obviously solves the F key issue, but then keyboard shortcuts lose out as you're left with only one Win key, which is on the right of the spacebar. Some days I love it, others I can't stand it. It's a well build keyboard, but I'd have to say that the build quality isn't nearly as robust as RealForce. If the HHKB had a Fn *and* Win key on the left of Spacebar, I'd use it much more than I do.
If you mouse for most of the above, forget everything I just said regarding the HHKB.
If you plan to do a lot of writing, I'd suggest either the variable or 45g uniform 87U. Plain typing on the HHKB is a pleasure. And if the above mentioned issues I have with it are of no concern, you should consider it as well.
If I had to have just one keyboard, it would be the 87U variable. It's also my choice for FPS gaming. But if you end up like most of us anal Topre snobs, you'll have to have them all anyway.

Good luck!