I haven't tested both, but 301x apparently has Koto outer ply. BO2X has Limba outer ply. The BO2x probably has softer feel and better control. 301x has Koto outer ply so it probably feels slightly crisper. Probably overall similar speed and spin though.
I have tried both Fang Bo B2X and Fang Bo B2. I found that B2 is better in many things such as, good feeling more control. In term of speed, B2 is not significantly slower. I combined B2 with Joola tronix ACC on forehand. It's good enough to generate power and spin so easy.