Has anyone evaluated the Tek MDO3000 SA yet?
A lot depends on what you want to do with the analyser. The MDO is effectively a high sample rate 8bit ADC +DSP with a 3GHz capture range.
The Rigol uses something like a 14bit ADC with a few MHz of bandwidth at the final IF. So it also has a multiple conversion up/downconverter section ahead of the ADC.
So these instruments will have a very different set of limitations to their performance. For general RF research and design work I would find the MDO to be a very interesting bit of kit because of the uniquely wide capture range it offers. But it could never be the only spectrum analyser I own.
Both the MDO and the Rigol have poor phase noise and both will have very limited spurious free dynamic range. I would expect that a skilled user of the Rigol will be able to dodge the DR issues more successfully than they would if they used the MDO. This is partly because I'd expect the MDO to have a lot of spurious responses onscreen even if you just fed it a single cw tone. There isn't much you can do about this and this is one area I'd expect even a cheapy analyser like the Rigol to easily outperform the MDO. But it depends if seeing lots of -65dBc (typical) spurious signals is an issue to you?