Oh it is good gear, but the list of 'bugs' and 'erratas' on the gear is growing longer and longer for every month it stays in service. Spare parts are almost impossible to come by, and even the toolchain needed to update the programs are old enough to require special dedicated workstations.
It is not a matter of 'working' it is a matter of 'will work in the future'. Right now all the gear has reached "end of life" and spare parts are very close to being "ebay if you're lucky" in terms of procurement. Trying to get the customer to upgrade BEFORE we're already screwed and have to 'rush' an upgrade is the game we're in now.
Doing a 3 year project in 6 months (while in some cases doable..) leads to badly rushed design and future redesigns. We've seen this over and over in the past 10 years.
An example is that the new hardware has built in EX barriers on each channel, the termination boards are much better and a variety of other improvements. This translates into -4- massive cabinets being reduced to one. Real-estate offshore is hugely expensive and this would save staggering amounts of money compared to expanding equipment rooms... but they want the stuff they're used to, not the stuff that is current.
The hilarity of the whole thing is that the 'current' stuff is now installed all over the rig where old hardware is not available so now we have both systems running in parallel with a ton of 'interfacing' and single points of failure introduced as a result.
It can drive an engineer mad.