If it is selling for 45 dollars the BM is most likely an Ascent model. Not a bad knife, but not a real stunner either.
While the Delica is a good knife as well, significantly superior knives can be had for only a few tiny dollars more.
If I only had fifty dollars to spend on a knife I would do something to earn, find, or save ten bucks and go buy a Griptilian. It has the Endura/Delica beat in most major categories.
Handle - Unlined flat nylon vs. Steel lined contoured nylon. The Griptilian is stronger and much more comfortable and secure in actual use, albeit at a slight width and weight penalty. The steel liners add rigidity and prevent that cheezy hollow feeling that you would otherwise get from unlined FRN.
Lock - Lockback vs. Axis lock. No contest, the axis lock is stronger, more reliable, smoother, more convenient, and much better at adjusting for wear. I have never seen an Axis lock knife with discernable blade play after months of use, lockbacks frequently have significant blade play even when new.
Blade - Thin and pointy vs. Other. I have seen too many Delicas with the last section of the blade broken off to get one myself. The extremely thin point is good for penetrating, but just doesn't have enough support to be really durable. The shape of the 555 and 556 are still excellent performers, but they have more steel at the tip for additional strength.
Frankly, I would be willing to pay the extra ten bucks for just the steel liners or the Axis lock. Getting both makes this an easy choice as far as I'm concerned.