In a head-to-head shootout, the best tube phonostage will have a slight advantage over the best SS phonostage, IMO. A well-designed and implemented tube stage offers all the detail and clarity but doesn't come across as analytical as its SS comrade. The tube stage also has a warmth and intimacy that SS just can't match. Of course, I'm biased toward tubes and there are downsides. A good tube phonostage or pre will cost considerably more than a comparable SS design and there are cheaper SS stages and pres that will do a fairly good job while less expensive ones with tubes have compromises - they tend to be noisier and lack bass control.
If you're looking for a phonostage or pre that handles MC carts, it gets a bit more complicated in that with tubes, you'll need either a step-up or FETs. Step-ups are preferable but good ones are expensive and all need to be carefully matched to your phonostage and cartridge - anything less than ideal results in noise and roll-off. FETs are easier to implement and use and tend to be cheaper but will omit some of the warmth and intimacy that folks want from tubes.
I've had quite a few p-stages and pres in my system and my preference is for pres with the 417a/5842 based Loesch circuit. Although they aren't cheap and certainly have detractors, they are quite flexible (settings, gain) and have a purity and intimacy that I haven't heard from the other phono pres. Of course, your system and requirements may be quite different from mine so take it with a big grain of salt.
