1. centralization of development, only a few people can publish miner for FPGA. In the face of much lower than expected hashrate and profit, you can only be forced to accept.
2. risk of open source, if open source, is likely to be taken by the third party to make MPW ASIC, which does not require much money , but return is much higher than FPGA.
3. risk of warranty, FPGA is quite different from GPU, it can not real-time monitoring the running state and cannot quickly adjust the frequency, when so you notice the running state exceeds the limit, it is late. Maintenance may be a big trouble , the FPGA is very expensive, if the FPGA chip burned, that is equal to the board scrap.
4.algo risk, altcoin developers may change the algorithm, GPU can quickly adapt to the new algorithm, but FPGA developers cannot be so fast ,when he worked hard to develop a new miner,the algorithm may change again.
At present, FPGA miner is unrealistic and some is obviously scam.electricity fee is not the main factor for altcoin mining.
[,,,]
ROI and electricity fee are not important, because GPU and CPU can bring dozens of times more revenue every year.
the main draw for me is power usage. my electric costs are high and fpgas are an answer to that.
1. as for developers, it seems most bitstreams will have a devfee, that incentives development.
2. sure but tapeout still takes time (2-3 months?) in which the fpga will rule. then change algo again perhaps.
3. true, easy to burn it up. so, run vetted bitstreams, observe proper cooling, do monthly maintenance.
4. for algo changes, depending on what changes in the algo i believe ive heard a few days for the new bitstream to come out with most of that time being compiling (or whatever its called) the new bitstream
but hey you may be right. i just ordered one, we will see how it goes. and yes i am aware i may of wasted 3.6k USD. if so oh well at least ill have a cool toy to learn VHDL on.