I really wish people would stop calling FPGA's ASICs. Baikal (so far) has only made FPGA mining rigs. There is a huge difference between an FPGA and an ASIC. An FPGA is not that much different from a GPU. Anyone can get one. Anyone can buy a Zynq FPGA board from digikey for $89-$199, or a higher end one for more money, and if you take a little while to learn how to program it, you can hash any algorithm except equihash & ethash. Furthermore, your ROI will be better than a GPU in almost every case, in some cases dramatically better (as Baikal showed with the X10 and Giant-B).
Are you really sure that Baikals X10/B are FPGA? (Which FPGA, by the way?) While it is enterely possible, technical characteristics of these products are not typical for FPGA. Especially the low power consumption.
As for ROI I wouldn't expect good ROI from entry and mid-range FPGA boards because of their weak power supplys. We need propertly designed professional grade DC/DC for core voltage, that is rarely seen in practice.