It's certainly more risky when you are buying hardware only to mine - although I guess that is bounded by the fact that even if FPGA or ASIC miners were to make it unprofitable, the GPUs are still valuable and you can sell them.
Yes, there is risk in buying dedicated hardware but the risk is quite reasonable. The R9 290x GPUs are brand new and in high demand. If for some reason the altcoin market collapses I can sell them close to their original cost.
