I for a long time was buying Stew-mac maple radius blocks, than thought I'd try the LMI's. I ended up sending back the LMI blocks for a refund. They are not one piece Maple, don't evan think they are maple at all, but what's worse is that they are multi-piece. The Stewmac's are expensive but worth it, one piece maple. I've heard that evan they are not perfectly accurate, but I also have the Stew-Mac 12" radius aluminum for final touches.
I think it's a good idea to have the other side in use, on mine I used other blocks to sand a reverse radius so I could use it for stuff in need of a reverse radius. Maple is expensive wood, and it wears down machining tools, all that results in a higher price. LMI's description at the time didn't mention that they were multi-piece and the pics didn't reveal that. I supose my feelings are not the all and all authority, but I didn't want to take a chance on them. Unlike a flat surface such as a straight edge or fret leveler, it would be more difficult to know if they are warped, and if so, how could you re-calibrate them? If they made them out of machined granite blocks, that would be alot more accurate, and they'd stay that way. Stew-mac had offered a much more expensive radius sanding block set, I can't remember what they were made from but a well known luthier had endorsed them, maybe sales were not keeping them in demand.