I do not know what the devices discussed cost, I would, however, sprint the $500-1000 for a good reconditioned Tektronix.
The worst cases I have had of debugging have been those where my instrumentation did not show what REALLY was going on.
I will refuse to work with a cheap scope.
20 or so years ago a highly qualified engineer and yours truly spent 3 months chasing a ghost and until we gave up on the instruments and started logical reasoning and realized possible causes and looked for those rather than what we could see, we got nowhere. The umpteenth guess showed up to be the reason and when setting the scope to hunt for that particular pulse we managed to see a itsy bitsy blip from a 2ns or so pulse. The reason for the failure turned out to be that the 74xx chips from a new vendor were faster and thus intermittently reacted to that itty bitty pulse.

Do not short change yourself on instruments, an instrument that does not show everyhing is 100 times worse than no instrument.

Erik