Frame Warranty
Montauk Hardwood Bikes warranty: lifetime warranty against defects in the material and manufacturing of the frame for the original owner. The warranty is for the original owner only and is non-transferable. This warranty does not cover damage incurred by accident, improper maintenance, misuse, abuse, or neglect.
Weight of Bike
My road bike weights in at 18.5 pounds with its current setup. Thanks to the hollow construction and engineering that goes into every bicycle, the frame weight is reasonable. For reference, a high-end aluminum bicycle (Cannondale CAAD12 Disc with Dura Ace components) comes in at 17.7 pounds.
Frame Strength?
My mechanical engineering senior design project (2014-2015) was based around testing and manufacturing wood road bicycles. We tested the pull-out strength of the headtube area which typically is the area of highest stress. It pulled out at 1750 lbs on an Instron tension tester, well above any stress normally placed on a frame. In the previous year, the senior design group tested the frame's seat stay area under compression by loading the bottom bracket area: it held up to 1620 lbs on the tension tester. They also tested the frame to a European pedal fatigue standard (DIN EN 14781). This safety standard calls for an 1100 N (roughly 250 lb) force to be applied to the pedals cyclically for 100,000 cycles. It passed as well.
Also, I cycled across the country (4,200 miles from Washington to New York) on my wood road bicycle in 2015.
Overall, wood as a frame building material can be a good choice. The specific strength (the strength of a material relative to its density) of wood is actually higher than that of steel, meaning: pound for pound, wood is stronger. You can read more about that here: Can a Wood Bike Be Light, Strong, and Stiff?