The Detroit transmission I wouldn’t have any issues with. Probably the best option on the market for an ‘automatic’ transmission.
The Detroit engine could be hit or miss. I personally wouldn’t want to deal with one - last one was a 2021 and over the course of about 26 months it spent about six months in the shop due to injectors (50k miles and 80k miles) and issues with the ONE box and regen system (110k, 160k and 170k). The truck was towed each of the five times it broke down.
Specifically the 2021s were plagued with issues, but given the overall issues with the truck/engine, but I wouldn’t intentionally *pick* any of the newer Detroit engines.
Keep in mind, Western Star is essentially a ‘fancy’ cab stuck on a Freightliner. The truck you’re looking at is pretty much the same as a Freightliner
108SD which should be noticeably less expensive than the Western Star, while getting the same real performance.
Ultimately, the answer is if you are willing to deal with a Detroit engine and it’s potential issues, and if you have any other dealers close by. If you only have access to a Western Star shop, I could see the appeal. If you have other options, I would explore those.
Aside from the major breakdowns, the engine pulled well, and was smooth. A major downside, was the engine brake, which was less than satisfactory. It wouldn’t hold the truck back as effectively as it should have. That’s a combined issue with the engine brake, and the engine/tune. If you’re in hilly terrain with a load, it’s something to consider.