Help us a little bit:
Do you want to count frequencies above what you can use a scope for, or do you want way higher resolution that possible with peak-counting on the scope?
Do you want to measure one or several events that are too slow for convenient o-scope-peak-counting?
Do you want to log frequencies or time-intervals?
If you answer at least one of those with yes, then go for Universal counter.
Consider using a wide-band radio receiver as an alternative for high frequency stuff, you might be able to listen into your signal. Google for SDR dongle.
If you want to do digital stuff, consider a Logic analyzer (OpenBench LA for example), you can read the frequency and time intervals with that device, too.
If you want the convenience of connect to DUT and read frequency, go for Unicounter.
You should be able to get decent offers on ebay or other places where cleanout of labs appear, at a nearby ham radio swap I saw the younger brother of mine recently, the HP5334B.
If you only want frequency reading, a simple frequency counter is enough, a universal counter will help if you want to compare frequencies or have exotic trigger/arming requirements for example.
About everything you can do with a UC you can do with other stuff, e.g. adjusting the LO of a radio to a known good source of LO Frequency ? Wideband radio, Lissajous method on cheaposcope are available too. But without the convenient number readout.
I like my Box 5334A, but there are other from HP and there are also other manufacturers of course who make decent rigs.
What upper frequency limit do you look for ?
Check your space constraints, means check what fits best on your desk.
Get the manuals matching the offers on ebay for example from KO4BBs website, compare specifications.
A bad mother oscillator is not a no-go - you can replace it with something better.
A defect box is always a gamble, mine had defect not listed but was way cheaper than the others.
"only" had series resistors in input stages burnt, easy to replace. Mother oscillator seems to have been a Hameg
, so I stuck a OCXO from ebay in it. Works like a charm.