Allow me to ring in here. Sorry I didn't see the thread sooner. I own or owned a Placette Active Linestage, and Audio Aero without Preamp, added the preamp, VTL 7.5 & a CAT SL1 Mk 3. To confuse life just a little. The Placette was much better than the earlier generation of the CAT. The Audio Aero sounded better running through the Placette than running direct. Don't know why. My Placette was single ended $4500. Go balanced & really have fun although Guy will try to talk you out of it. Anyone who criticizes the build quality of the "interior" of the Placette. is nuts. No one can come close. His parts cost is one of the highest in the industry. Add a few hundred $ & have him use a nice case in a color you prefer. I bet you can get him to do it. He can also customize it for you if you need extra features.
Now my VTL 7.5 was very close but it had more synergy w. my MB 750 amps & really dealt well with the cancelation of noise in a fully balanced configuration. But it is very close. My system benefits from a tube preamp & fully balanced so it became my preference. I miss my Placette. It just worked. Those who criticize it owned the passive. Two different animals completely. The Audio Aero even being run directly into my amps in balanced was not synergistic (no preamp built in, meaning it is its own preamp but can't function as a preamp on anything else) with my system. After I added the Audio Aero full preamp section into the Capitole sound definitely changed. I don't know why. If I blind folded you to compare the Audio Aero direct to the Audio Aero through the Placette you would probably not get it right. The bass is a tad more solid if that. Somehow the Audio Aero does benefit from the preamp, I found out why but honestly now I don't remember. In the end it is very close. The ergonomics of the Placette leave a little to be desired. But Guy of Placette. is one of the nicest & most honest guys in Audio. He makes money, but only if you benefit. He will never try to sell you a gimick & stands 100% behind his product. Anyone criticizing the Placette really doesn't know what they are saying.
Now, using the preamp on my Audio Aero for my Meitner setup (don't ask, I have a lot of things going on these days) the Audio Aero is no slouch. It is a great preamp. I only paid $1500 for my upgrade & it basically gives you a mostly new unit. It is excellent as a preamp. I understand it now goes for around $2000. I am not sure though. If you want to save some money then do that. You won't be disappointed at all.
What should I say once you get to the top the VTL 7.5. Well it is amazing, but the jump between the Placette & it, really is diminishing returns on a large scale. I also bet, a balanced Placette for nearly double the price might compare very closely, but not ergonomically. Very few preamps will have the ergonomics of the VTL.
What would I do. It depends on what you want to spend. Each step up in money gets you better sound sort of. Maybe just different. Audio Aero preamp compared to VTL 7.5. The 7.5 is better, but the Audio Aero is still great (surprisingly good once you compare it to anything). It depends a lot on your system. You can save the money & have fabulous sound. Most audiophiles won't ever know the difference although they say they will. I would as GUY Hammel says it, save some money & spend the rest on music.
My longest post but I really hope I helped.