I picked one of these up about a month ago at my local.
I wanted to start learning open tuning and slide without spending alot.
A Godin RG3 is my main guitar but with the vibrato, changing from standard to open tuning was not an option for me.
I went through a selection of SG's..and some other hard tail double cutaways hanging in the store.
All unplugged and through process of elimination.. comfort..feel, weight and resonance I narrowed the field down and kept coming back to the Yammy.
Solid, stable guitar, pretty good tuners, great neck ...sold!
I brought it home and dropped a Bartolini (that I have had for years) into the bridge slot..similar DC resistance to the stock pups in the guitar.
To my surprise the stock pup sounded very good compared to the Bart.
The only issues...weird taper on the vol pot. and the tone pot was 250k..it dragged down the output vol. ever so slightly when connected so...
Changed both mini pots out for standard size 500k's...yes they will fit into the cavity.
The shielded cable from switch to output even though only a few inches long was microphonic ..changed that out and all is quiet.
Pickup selector has a good feel when changing positions, seems well made and should be reliable.
Only one other addition was a Schaller roller bridge from Stew Mac's and a switchcraft o/p jack.
The guitar stays in tune very well and after a bit of graphite in the nut, tuning changes are quick and accurate.
The balance is slightly neck heavy but not bad at all.
Well worth $400.00 +-