It has been a couple of years since I worked on this thread/issue, but in a nutshell to explain where I ended up in all of this: I went Whest young man I went Whest.
After an extensive amount of time using the Clear Audio Smart, a PH10, the Nova III with external power supply, then a Whest Three signature and it was a wow moment. The Whest Three blew everything above off of the bench. Hands down, no comparison. You do need variable capacitance input, that is an absolute, but if you can match the input to the cartridge you plan to use, you can go with a fixed number if its in the approximate range when added to the capacitance of your cables from the turntable to the phono stage. I was shooting for around 250pf total with my AT20ss. I loved the Whest Three so much that I decide to have James at Whest custom build me a hybrid Whest PS 30 RDT SE 2019 which used the board from the new PS 40 RDT, the case work of the PS 30 and a custom input stage on one set of switches for 48 db gain and 91 pf capacitance which allows for 250 pf total when combined with my cables from Toronto. It is a very striking improvement over everything I have used to date. All of the engineering on this was done by James as he is a huge fan of the AT20ss (he has one too). He modified one input on the phono stage which is normally set at 70 db for extremely low output MC cartridges to use for the MM input.
After doing all of this, I found a deal on a nearly new Ortofon A90 MC and installed it into the Turntable and set it up on the 65 db gain input. I was so impressed with this cartridge that I have not put my beloved AT20ss back in!! I never thought I'd replace it. The AT20ss is 90 % of the A 90 MC, but that extra 5-10% is enough so that I am leaving it in place. Plus James told me that his A 90 MC was re-tipped in England by Expert Stylus with their Paratrace diamond and it is even better. When mine wears out, I'll try that tip.
James also suggested that I go to their audio interconnects for the phono stage as they use broadcast quality cables which are phase aligned and jump things up to a whole new level. These are the same cables they supply with the Titan Pro and Reference MKIV phono stages which are at $11K and $18K in price. I will try that one of these days too, but the cables are not inexpensive.
So overall, I think that you would do very well with the Clear Audio Smart V2 which is an outstanding phono stage for the money. It is not in the league of my Whest gear but it's also 5 times less expensive. However I think I like it almost as much as the PH10, if not more. It certainly has a much nicer sound stage which is more open. The mid range is smoother in the PH10. The Nova III is better than either of those two, but at a little more money with the external power supply. NONE of them come close to any Whest phono stages, hands down. If you ever see a used Whest for a good price, buy it. I sold my Whest Three Signature with the outboard external dual mono power supply after a long time of dealing with a bunch of tire kickers who had no idea of what I was offering!! These guys didn't know a good deal right in front of them. I lost money on it, but it ultimately ended up in a good home and the guy just loves it.
I'd buy a Whest Titan Pro if I ever stumbled upon one, but they are almost never up for sale. If I do, my custom built PS 30 RDT SE 2019 will be on the market :)