Which should I buy? Roller skates? Or Roller Blades? I like both which ones are smoother on regular streets?

I haven't used either recently but I found blades (in line skates) much easier than traditional roller skates. So I would go for in line every time.

Roller skates are safer. In order to use roller blades you should have ankles as strong as it takes to ice skate. imo

I find rollerblades easier and I weigh 300 plus pounds

I like roller blades on streets