As a die-hard anti-Unity Acknex user who switched to Unity, I've gotta say that Unity doesn't suck.

I love native support for .blend files, everything "just works" on whatever OS I build it for, an abundance of features in the free version (which I'm still using, because I'm poor), GUI.matrix (how I make KarBOOM's GUI scale to fit any resolution or aspect ratio), and realtime interaction with all objects in the editor.

I don't like the limitations of their particle system and the abundance of fairly useless non-deterministic physics functions.

But I strongly recommend Unity.