I’m deep into 500 series and happy to answer/blab about it.
I’ve had and sold the R Neve tape emulator. It’s great, subtle as mentioned above—it’s more color than effect. If you want one you should get one and see what you think. The silk buttons are good for two different tonalities of saturation (again: subtle). Like digital tape plugins it is best experienced when you run all the tracks of a multi-track recording through it (one at a time, not just one mix bus).
I liked it and you shouldn’t view me selling it as a negative—I buy and sell and try out stuff as much as I can afford (not as much lately haha). If it were back in my setup I would definitely use it often.
It’s going to give you: very mild compression ala clean tape (I liked using it to round off those outside edge transients that blow up digital true peaks and cause distortion in MP3 transcoding) and a choice of two transformer colors (or no transformer color if you prefer).
In general for 500 series my focus has involved learning when/how to use transformers creatively and effectively.
For anyone looking at racks/boxes: I run BAE racks and lunchboxes but recently got one of the new Cranborne 8 slot boxes and that thing is fantastic. Definitely recommend. The BAE are nice too, but if I was just getting into it I would go with the Cranborne.
Re modular @vinc:
Many of the preamp modules have DI inputs that either include or specifically avoid a transformer depending on your taste. Many also include both a Gain and Trim. So you can set the gain where you want it and then use the trim to attenuate for your converter. Nearly all the pres will also have a pad so you can hit the pad and then crank gain to where you like.
I have recorded many things directly from modular to 500 pre using a 1/8-1/4 TS into the DI of the 500 pre (and the pad!!). I’ve also used modular output modules and come in at line level and worked from there.
Depending on what you are after in terms of sound (clean, transformers, etc) you can select the pre you want and that has the features which work for your workflow.