Yes 1mbps is running on wimax network. And it availability depend on your registered location.
Last week my friend want to apply it but been told that his location is fully occupied.
From other source mentioned that Yes dealer stop assigning Yes 1mbps from YTL.

Above true or not, you may need to visit your nearest YES dealer to confirm it. Be aware that it come with contract if you applied it.

About the connection quality, you may need to try it because your location distance to network tower make the different. To save your pocket from the contract penalty. Do ask Yes Dealer nearby your area to do network test at your home or borrow yes device from your friend to do test.