Yeah, I downloaded UE 4 a couple weeks ago. I really like the play-state rendering and take screenshot for product promo images using it. I love the lighting and the procedural materials. Although I admit there are far more options than I'll likely ever use.
I did get transparent UV imports to work. Just make sure you have a partial opacity in PNG format for your UVs and it should work fine. I imported an OBJ model of a glass flask. I got the transparency, but without refraction, it didn't look as realistic as I wanted. So I just tweaked the starter content glass material. I can live with it now.
My latest victory was using materials to create a flickering flame and a translucent/emissive mat for a candle. I'm impressed with UE 4's material and lighting qualities. But I still have a lot to learn. I'm looking at it mostly for ArchViz and model staging use, but I still get a 'game dev' idea every now and then. It subsides when I start mentally planning the logic that goes into a game.
These days, I'm diverting my attention to building an alchemist's workshop scene for UE 4. I don't have any plans for it. I just want to use this as an opportunity to learn more about the animation and interactive features.