Ted Weber makes great speakers. They are generally made to tighter tolerances than the Eminence, although the new Patriot/Redcoat series of Eminence have really closed that gap.
The speaker that you asked about specifically - the 1230C-55 Silver Bell is Weber's equivilent of Celestion's original G12H30. The current production Celestion equivilent is the G12H30 Heritage...which is quite an expensive speaker (about $145.00 ea. if I remember correctly). They are not just good or great speakers...they're beautiful speakers.
As far as I know, Eminence has a G12H30 version in the Wizard, but it's not 55HZ. I don't recall a 55HZ Wizard.
The only Weber's I currently own are a pair of the older C12N's (12F50 by today's numbering). Mine are 25 watt ea., not 50 watt. They sound every bit as good as the old Jensen C12N to my ear...not quite the same, but with the same resonant qualities. They are heads above the Jensen re-issues.
BTW: For a reference point, the original Celestion G12H30-55HZ's were in many of the old Marshall cabinets from the 60's. The highly touted tone tone from that era came mostly from these speakers. Expect the Webers to deliver similar sound performance as the Celestions...although I wouldn't say they're the same.