I have an old fondness for these low-power, high-performing SPARC systems from days gone by. A 64-thread little monster, with 64GB of RAM, and a couple TB of storage makes for a beefy little database and file storage system. Sadly, that's about all that runs on these any more.
No, it isn't a top-performer any more. I haven't done it, but I suspect a legit performance test might show that my 16-core Ryzen probably performs better, even though the system has half the RAM (and the whole pool of RAM is never used anyway...). The drives can be mounted wherever, too. At the same time, that Ryzen draws more power, even with less electronics in it.
For my uses, the T1000 still does a great job. I got it used, off eBay for less than I paid for the RAM in my Ryzen system. Out of the box, Solaris supports zones, and offers virtualization and "containers" (as we call them now) to isolate processes without duplicating system bits, like a virtual machine does.
The drawbacks are becoming about the software that can run on Solaris, and the integrated system required to keep it running.
For the software, part of the problem is that few people write Solaris compatible bits any more. This is further exacerbated by its aged SPARC CPU, which has an even smaller following. This was made even worse when the premier source for finding the built binaries of FOSS software for SPARC Solaris shifted to a premium service model. I'm fine paying for the help getting the things I need, but the required subscription model and cost were more than I was willing to part with. Further, the latest Solaris isn't even supported on the aged hardware. So I have the few things that either come from the source with binaries that work (like MySQL, PERL, and Java), or I fight and struggle to build from source (which is also difficult because some of the compilers and OS libraries require service contracts to get). Really, the hard software runs on the x86 LINUX hardware (including the one made by Sun).
The T1000 doesn't have an I/O system, and requires either a serial or network connection. I don't have the stuff to make a serial connection work any more (does anyone have a dumb serial terminal any more?), so I rely on SSH or web. Sadly, I can't get the integrated web server to accept a modern certificate, and all of my browsers have ceased to accept the "trust this expired certificate" option any more, or accept the pre-TLS1.3 offering it makes. Similarly, the SSH offers a cipher, so my updated SSH clients don't allow me to connect, despite any settings I try to make work. Thankfully I have an older tablet with an older SSH client that does work.
Really I only need it to power on or kindly shut down the box. I recently had to exercise this in a power outage that outlasted my UPS. The system powered on and waited patiently for me to connect and boot the OS. It's supposed to do that by itself, but only does when I cleanly stop the system (and I haven't found the magic "always" setting to make it always boot after powering on).
It seems like the certificate and cipher problems might be solved with a firmware upgrade, but Oracle doesn't share these like Sun used to. You need to have a service contract with them to gain access. For a reasonable price, I'd pay, but you also have to have a certified piece of hardware to get a service contract. While I've done nothing that should de-certify my system, I did buy it second hand, and have opened it up to peer inside and added hard drives, which may or may not be on an approved list. I can't find where to understand what this process might be like, but after trying to get the last firmware upgrade (which I eventually found on the Internet) by buying support through a host, I did learn it's an expensive and arduous process (or so they sold me), and buying a contemporary server would likely be better in many ways.
So, with the waning opportunity to connect and turn on the system, it seems it might be time to migrate all of the storage and databases to another system, and figure out how to pass this one on to someone else.
It's a sad day, and the end of a small era. And a likely jump in the electric bill.