I looked at the chinese units when I was in the market, but I was nervous about how well they would work. Scope is one thing, but a spectrum analyzer is a bit more complex and harder to copy. They certainly seem to have limitations on the BW settings, readout accuracy, attenuator steps and frequency accuracy. I ended up buying a Tek 2714 on eBay for $ 600. Had a small problem that none of the faceplate buttons would respond, but turned out to be a 74LS... that had crapped out on the faceplate PCB. 3 hours each disassembly and reassembly plus a 50 cent chip fixed the problem. The 2714 is a 2712 with additional capabilities for TV cable network testing. 9kHz to 1.8 GHz range, with AM, FM and video demodulators built in. You can exit the cable TV mode and have a standard analyzer. The other change I made was from a 75 ohm input to a 50 ohm input. Simple enough. The faceplate input jack is F/BNC to SMA behind the panel. This jack has a 25 ohm R built in, and connects to a 50ohm attenuator. I bought a BNC to SMA bulkhead fitting, which was almost exactly the same size, with no internal R. Recal'ed the amplitude and now it is a 50 ohm unit. Works great and built like a tank. Only negative is no TG, but for most of what I need, not a problem.
paul