Hi Pani,
That is a bit of a tricky question, as my answer is going to reflect the bias of my experience with these decks. They are not all the same, and in my experience, even decks from the more well known restorers are not all equal either, as much as we would like to think that they should be...
One of the quietest running 301s that I have come across happens to be a mint condition Hammertone. It's motor was very quiet, as was its idler assembly, and bearing. It was also the best looking, by far.
One of the worst condition 301s I have ever seen was also a Hammertone. I received it for a full service from Malaysia. It was missing most of it's paint, and there was corrosion under some of what was remaining of the paint. The motor coils were a bit noisy, I was highly skeptical of this deck. The owner wanted to keep it as original as possible, for sentimental reasons. The bearing was good, showing little wear. By the time I had fully cleaned it up, rebuilt it, and tuned it for quiet running, mainly the motor needing work, as the coils were noisy, my appreciation for this deck had grown a lot. I was able to quiet the motor considerably. For it's obviously, very heavily worn condition, it was still very beautiful, and still played music pretty well.
I think the Hammertones look better.
Sonic wise, In my opinion, the biggest issue between 301 motor units, is how quietly they run. Aesthetics can all be changed, linkages re-plated, the commonly replaced parts all replaced, all that, but how quietly the individual deck can be made to run is what will be the limiting factor in the true performance of the deck, that is my opinion. During playback, the noise level of most any well sorted 301 is sufficiently low as to be mostly a non-issue. If you turn the gain way up and place the stylus in the dead wax, a place in the vinyl groove where there is no, or little content, and then you can hear the mechanics of the 301, or by using a stethoscope. Really, this borders on listening to the gear, and not the music, but I suffer from being a little bit of a gear head, and I like my decks to be as absolutely quiet as possible. In my experience, the idler drive is the biggest source of noise in a 301. It is well worth making sure that it is running quiet.
Yes, belt drive decks can be quieter. But some of the idler drive decks have a little something magic in the way that they can help pull sound from a record groove. That is why people love them.
If you get a deck from Loricraft, or Audio Grail, you cannot go wrong. As to if either one is better, or even a deck from another reputable refurbisher, that will be dependent on which deck is actually best, and quietest. There are subtle differences among many of them, most all.
Do you like listening to mono? or 78rpm? if so, get a grease bearing, Hammertone if possible.
One difference that I have seen among different restorers, is which parts are replaced. I have seen some decks come in, restored, with original springs, and the spring damper rubbers loose on the spring. Those dampers are there for a reason, and they are important. Not sure why anyone would not replace them. With AG, or Loricraft, you are good.
My reference deck is a high spec Linn LP12. It used to be top spec, Radikal, Naim Aro, Dynavector XV-1s, Keel, Cirkus, etc.. In side by side tests, some well equipped Garrards have fared very well. The Linn is always a quieter deck, that is not a question. Sound wise, I never did really make a solid decision, as I did not want to swap my cartridge and such around for I love both decks. That LP12 was pushing $20k, the Garrard, a little more than half that. It was not really a fair test.
I love the Garrards. I like 301s better than 401s. 401s might tend to be a little quieter. (In a 401, I recommend going for the flush strobe model, as there are differences in the motor, and in most of the raised strobe models, there are switch contacts that tend to break in time due to the design. These contacts are very difficult to fix, it can be done, and a replacement switch to match is nearly impossible to find)
