Is this a Tektronix MSO4000?
If so, look at the probes. TCP0030(A) and TDP0500/1000 can be had on ebay for amazing prices compared to new and with these probes + Tek MSO4000. I don't think you can beat the functionality with these probes for the price.
Working TCP0030/0030A 30A 120MHz current probes usually go for around the $1200-$1500 mark. Working TDP0500 and TDP1000 go for around $500-$1200, depending if they come with accessories.
That's not any cheaper than what you can find for other manufacturers. For example, LeCroy CP031 current probes can sometimes be found around the $1000 mark, and I've bought quite a few Active Differential probes like the 500MHz AP033 and 1GHz AP034 with the 42V high voltage adapter for notably less than $250.
Agilent/Keysight, by nature, is a bit more expensive. A N7026A current probe will fetch north of $2k, but an Agilent 1159A 1GHz active differential probe (which, aside from the probe interface, is identical with the LeCroy AP034) in working condition can still fetch close to $1k.
The price difference however is hardly a reason to settle for an inferior scope. Even less so when considering that both LeCroy and Keysight offer adapters to use Tektronix probes with their scopes.
I've been looking for comparable probes for my DSO-X 3034A and the market is not good. I ended up buying the adapter to use the older Tek TCP202 probe on my Agilent, ironic. It seems that in this generation (if you are talking about Tek), the Tek probe selection dominated.
Based on what, what is available used and worn-down on ebay?
Also I don't think you can't beat the capture depth on the Tek unless you spend way more money on an Agilent.
Not true. The MDO4000 has 20Mpts of memory, and second hand variants, even the lowly 200MHz models, often go for in excess of $5k.
For roughly the same price you get an Agilent DSO8104A 1GHz 4ch scope with 128Mpts of memory. Or three LeCroy WavePro 7300A 3GHz scopes with 64Mpts.
The only real highlight of the MDO4000 is the built-in "Spectrum Analyzer", which, although only being an FFT analyzer with woeful RF performance, can run in parallel to the scope mode.
Until recently we had a MDO4104C which was carried around by an engineer for a specific task where it is useful to have waveform and spectral views in parallel, however this is now in the process of being replaced by a normal scope where FFT will take the place of the MDO's "spectrum analyzer".
And the Tek 4000 series display is far, far better than the Agilent/Keysight options.
I don't know. The MDO has a decent 10.4" XGA display compared to the smaller DSOX3k's display (the DSOX4k has a larger 12.1" display, although both are SVGA only), but then the MDO displays up to four channels, digital channels and the spectrum view which is more than what you'd see on a scope like the DSOX.
It seems that even on the larger Keysight scopes they may be using this crappy display resolution that comes on the DSO-X 3000.
No, they don't. SVGA is only used on InfiniVision Series scopes, which cover the entry-level up to the mid-range market. The larger Infiniium scopes all have XGA or better displays, aside from the early 54800 Series which came out in 1998.
I never thought I would care but when you are using the scope every day and looking at lots of edges you suddenly realize that the display resolution is really important. I theorized that Agilent may have settled on this poor display resolution because a higher resolution is irrelevant due to the memory capture depth limitations(and inability to control this on some models).
That theory of yours has no relation to reality. Fact is that both the MDO4000 and the DSOX are 8bit scopes, which gives you exacly 256 vertical steps. It doesn't matter what resolution your display has, as long as it can display 256 vertical steps then any higher resolution will not add information (i.e. details) to the waveform. Simple as that.
What Agilent has realized however is how important a good user interface, simple operation and immediate response is for a good scope. This is something Tektronix never understood. The MDO Series has a horrible user interface, and like most Tek DSOs it locks up when it's doing something demanding. Tektronix still has the slowest architecture on the market, and that includes even newcomers like Rigol and Siglent. All while LeCroy and Agilent/Keysight have been pushing scope technology forward since the end of the analog scope era.
And this is one of the reasons that the DSO-X still sells like hot cakes and Tektronix has been struggling with dropping sales for over a decade.
If you are working directly with TestEquity maybe they will let you look at a few scopes in person?
I'm sure they will, and they will charge you through the nose for it