I don't think the actual brand matters so much as long as the N-P-K numbers are relatively similar. Most fertilizer should have 3 numbers specified on the package somewhere (like mine, which is 7-9-5) ... if those numbers are close to each other, great. The nutrients should be complete and balanced. Cactus/succulent specific fertilizer is a gimmick to sell more product. Any (decent) fertilizer will do. What matters more than the brand or whatever is the dose. Whatever they recommend on the package is usually too high, and you can use 1/2 to 1/4 of that amount and get good results most of the time. Whatever you do, don't use more than they recommend, and be careful to water it in well.
