Tri-tip is a wonderful cut of meat and is a favorite in our house. We always do it grilled, usually with a reverse sear method- low heat (under 300) then finish the last few minutes over direct fire to give it a nice crust. Pull it at 130* internal, let it rest in a tent of foil (don't wrap) for 15 minutes then slice perpendicular to the grain. Tri-tip will do just fine in the oven, you just won't get that wonderful charcoal or smoke taste. I keep it simple with the seasonings and let the meat do the talking: salt, pepper and garlic is the way they serve it in Santa Maria.
Honestly, tri-tip will come out great as long as you follow these two rules.
1. DO NOT overcook it. Cook to medium rare
2. Be sure to slice directly perpendicular to the grain. The grain structure of tri-tip changes in the middle of the roast, make sure you adjust your slices to make sure you keep slicing perpendicular. I've seen perfectly cooked tri-tips ruined by improper slicing.