My wife got a good deal on a "beef round sirloin tip" roast, about 13 pounds. I'll cook this on my Traeger, but I am not sure how this cut should be cooked. I think there are 2 options:

1) cook it like a brisket, i.e. 225 deg F until internal temp is about 195-200 deg F

or

2) cook it like a prime rib, higher temp to medium rare?

Any suggestions?

#3 - It's a sirloin roast and cook it to the temp you'd cook a sirloin steak. I cooked many of these when I lived in Calgary as brisket was about $110 whereas a sirloin roast was about $22. I always smoked mine at 225F (I also smoke prime rib at 225).

Here is a sirloin roast I smoked in Calgary:

195-200 way too high IMO. Beef Med Rare will be about 140.

I think you could do it either way. Upside of the lower and slower will be that you'll get more smoking effect IMO but you may get the outer rings more well done while the center gets to MR or your desired doneness.

My 2 cents.

Low and slow. It doesn't have the fat in it of a prime rib.

I had one of those a while back. I cut a couple of honking steaks off the front side and grilled them, made stew with part of the back side, and have at the tip piece from the back side that I will smoke at 225-250.

If you cook it like a brisket it will be like shoe leather.

I'd just do hot & fast on it to med-rare.

low and slow,

I cooked one a few years ago, about 10 lbs,

internal temp probe, pulled at 110 , wrapped and let sit in cold oven for a few while I prepped sides,

turned out a perfect rare to slightly med rare on edges,

don't let the sirloin name fool you, if it is a true sirloin tip, it's actually a beef round tip (primal cut is called a knuckle)
it does not have much if any internal fat (just very light marble on a prime piece if you can find one)

tri tips and a few other regional names may be the cap that is on a whole sirloin,,

(Sirlion steak btw is usually called Top Sirloin )

cook it like you would a top round etc as it is more like roast beef than smoked brisket

Salt crust and 200F. It'll take all day to get done, but oh, so tasty. The trick, explained to me by a chef, is that you do not want the juices to boil. So, anything under 212(ish) is good.