Setting the SPARC bits aside, I feel like the Ultra 20/24/27 machines were well-constructed 64-bit x86 machines with regular AMD and Intel processors and ECC memory and reasonable fans and so on. I don't remember how they were on price, but I feel like they were not outrageous when compared to similar lines from Dell or HP at the time.
I had a very different experience. I was responsible for about 100 Sun servers in the early 2000. To get to our server room, I had to go through another datacenter, where all was HP. We had every single week 1 or 2 outages (power supply, disk, mainboard, memory…) all the time. EVERY WEEk! Meanwhile, the other datacenter had just a few visits per year, for upgrades…
The pricing was the other Sun problem. It was a super grimy negotiation to get them down from their ludicrous publicly stated pricing to what you could actually get them for, which was more reasonable, you just wanted to clean yourself afterwards.
In the UK Sun had done some deals of the type that in North America are dominated by IBM (banking infra etc.), so they were probably absolutely milking those clients and giving the rest of us more slack than they wanted to let on.