Bosa Properties is a very good developer for sure! Lots of history and they will stand behind what they do. There are a few other development companies run by family members sometimes confused with Bosa Properties such as Bosa Development. Even Appia and Embassy development are all from the Bosa family.
A few other developers I like include:
The Wall Group (Wall Center, Yaletown Park, Wall Center False Creek, 2300 Kingsway, etc)
Aspac (One/Two/Three Harbour Green, Wesbrook at UBC, etc)
Westbank (Shangri-La, Shaw Tower, Fairmont Pacific Rim, now 6/Fir, etc)
Onni, Cressey, Concert, Salient, Intracorp, Aquilini, are all good too in my opinion. Quite a few good ones but Bosa Properties certainly would be high on the list!