I know I'm going to sound like a wanker, but both are "squares". Neither are square shaped. Pointless i know, sorry. Both have their uses. A framing square has it's unique capabilities as well especially if you use it with stair gauges. I have at least 5 different types of squares that I use for different applications. If I had to pick one to start.... I'd say a combination square, go starrett. For larger layouts...it's a toss up IMO, as i said both have their uses. Maybe if I had to pick a "master square" for my shop I might go with a large scale triangular one just to check everything else off of but. it could honestly go either way.