They can both be good. When using a tube phono stage, there is a great demand for quiet tubes when there is very high gain. This can cause some expensive tube buying. If you use a good quality step up transformer, it puts less demand on the noise factor in the tubes, because you'll get 20 db more gain, before it hits the tube phono section. With less gain needed from the tube section, the noise problem is less critical. With solid state phono sections, noise is less of a problem, but I think tube phono sections sound better, when they are done right.
Active vs. Passive Step-Up Devices
I would appreciate all thoughts regarding the relative strengths and weaknesses of active vs. passive step-up devices. My cartridge output is 0.25 mV.