Frankensteins or Audio Note Kit 300b

Get the Franks. Make sure you get the latest versions. They will hold their value and will resell easily.

What kind of speakers? That may influence the amp choice.

I have the Audio Note Kit 1 10th Anniversary Edition, and it's great, but there is a price and sonic quality difference between mine and the Frankenstein. If I had more money to spend, I would have it myself. There are quite a few owners here on Audiogon of the Frankenstein, and many of those have been through other world class amplifiers, and consider it to be one of the world's best in the low power SET 300b category.
If you are concerned about price, get the Audio Note, believe me, you'll be more than happy. If you do though, spend the additional coin and get the C-core version. If money was not a consideration for me, I would get the Frankenstein because members I respect that own it think so highly of it.

I have the Dali Helicon 800 speakers which I believe are about 90 db sensitivity. My concern is that the 8 watts from the Frankenstein may be somewhat shy of driving them, whereas the Audio Note will deliver 2o watts going with parallel 300b's.
I have an Art Audio 845 with 16 watts that drives them with no strain.

Specs on those Dalis also show 4 ohm impedance and fairly high watt recommendation. Not a great match to a low power tube amp on paper.