Oof… impossible choice.
The Voltage Block literally brings Elektron style P-Locks to Eurorack. It’s fierce.
However, I personally think that comparing Hermod to VB is approaching apples and oranges.
For all the sick and immediate features of the Voltage Block, I don’t think that it’s a master sequencer/brain per se. It does things nothing else can do, and in style for sure, but for organizing a sequence of patterns, or preparing for an entire performance I think it would not be the ideal choice.
I’ve come to see the Voltage Block as more of a performance tool, a P-Lock based freak out controller that is really fantastic. The best thing about it is that it’s patch related, so I can re rout myself and head off in other directions in a performance, and even re program it in real time (or set up a bunch of things and call them up with patch cables at different times.)
The Hermod is both my modular brain, and my extension for CV/Gate from the Pyramid. It holds my patterns, has an established architecture for input, output, patters, and more.
While Hermod has many features for performance, and can also pass other controllers through in real time, or record them and save them to be applied later, at specific times, or copies made and used elsewhere, organizationally for the structure of a piece, or a collection of sequences for an extended performance it is much more like a complete composition tool.
So I suppose it really depends on what you want to do. If you are looking to get P-Locks going, and want to freak out a patch, then Voltage Block is the undisputed choice.
If you are looking for deeper, more organized over all control for everything, then Hermod is the way to go.
My problem is that typically I would really like to have both. All the things please.
Naturally this is just my experience, and I’m weird. So I would suggest trying to get your hands on one of each (even in a shop with headphones) and try them. Neither are immediately gratifying without reading, learning, and trying a variety of things, but some hands on experience always tells the story best for me.