Double Keyword Insertion in Display URL's

Does Underline, Dash, NoSpace make a difference for QS

[lgn1]

Now that we have a new shorter domain name, I can add keywords to my Display URL to improve the QS, and perhaps improve the CTR.

Given the Factious keyword: Purple Widgets

which points to a page with quality content on purple widgets.

should my URL be:

www.example.com/PurpleWidgets
www.example.com/Purle-Widgets
www.example.com/Purple_Widgets

For quality score purposes are the above three identical?

I have heard that Google can understand two word combinations better when they are separated by dashes, but that was from a post ten years ago.

On another note, somebody mentioned that having a clean url with no keywords, added 5% to the conversion rate, but no statistics was provided, and I have no proof that the sample size was large enough to confirm the hypothesis.

[RhinoFish]

Generally, 2 will win, 1 will likely be very close (but could win now and then), 3 will lose due to underlining (at times). That said, the differences will be very small.

Google understanding things is trumped by consumer behavior manifested in your CTR. Write ads for people who you want to notice and read them.

I've seen no keywords win as well, but it depends on branding of your domain and how closely it ties into what you're selling.

Your Display URL is a very small factor - negs, ad text, match type, bid adj for mobile, geo targeting, even speed of site loading are far more important.