I particulary love and use these the most: Vintage73 (I haven't tried the gemini version yet.. but it's not a vintage unit..), V72 (siemens, three channels included), Titan Eq preamp (NoEq Pre Mid2 preset is my go to Helios sound!) but also the portico channel is very very nice - forgot the name (5033 mojo i think - i know it's not a preamp but it sounds good). Same goes for Girth Masterbus - the most awesome C******r color from Henry's pallete (although there are E*I/tg preamp samplings as well available..).
These are very colorful preamps - there are however very nice clean preamps too: G20 (GML), A****n, Millenia.. all good (GML stands out!) but I like vintage sounds.
1. They ALL are awesome and all have their uses. I haven't tried them all, but brother how I wish I owned them all!
2. Out of the ones I own, the Vortexion adds a very unique crispness to the sound that I love on pretty much anything. The Channel Strip Pre is VERY good for that type of flavor. My FAVORITE to use is the BG1. It's not the best for everything, but when its right... I don't have the G20 Pre, but I have several of the G20 quickmix programs and the texture of them is AWESOME! Very detailed and it really colors the sound in a very transparent way (I know that "contradicts" itself, but its really a special piece)
If I were you, I would get as many as you can haha
I'm the worst when it comes to GAS, I covet hardware gear like a crack addict lol Henry's preamps are so good that I honestly don't care when I get more hardware pre's. I have the E-M-EYE, NV Vintage, AyPeyEye,1959 v72A, the valve Channel and both the G20 and NV vocality. All amazing. I've never used a vintage NV but the NV vintage has a better tone then the vintech 573 I owned.
they are all great (i dont have all but i'm sure the rest are as good as the ones i do have). some may be better suited towards whatever sound you have in mind and want to achieve, but his prices are so low that you really can't lose. just but a handful that seem to have a nice variety, and play with them for a while.