Dell puts a fair amount of engineering into their servers (as do other main brands like HPE and Lenovo) so it's unfortunate they've lost their roots from the old mail order sales company.
If someone else is paying I'd prefer one of these big OEMs for established firmware lifecycle, spare parts and long gray market availability, shock (shipping) and thermodynamics engineering. If I'm paying, Asus or MiTAC (Tyan) are good enough.
I was fortunate enough to work with a fair bit of sun gear (3/260, 4/670, enterprise 250/450 and even some big iron 6500s) back in the day.
These days, I've got several Dell 5820 style workstations and I'm pretty sure someone who interned at sun in the 1990s is now running dell's workstation division. The medium sized dell deskside towers have nearly identical vibes as those old workstations, and are a pleasure to work with.