Teamviewer works across both platforms and is very simple and secure to setup and use.

LogMeIn is the easiest that I have ever seen. BTW, why not just use the Microsoft RDP connector for Mac (http://www.microsoft.com/en-us/download/details.aspx?id=18140)?

I believe LogMeIn is a good software, RealVNC is another option.

i can add to Naeems's good proposals : Timbuktu (http://www.arrisi.com/products/product.asp?id=1027) and GoToMyPC (http://www.gotomypc.com/remote-access/).
Configure carefully these softwares in order to have a strong security : no default or autologin access, very good password, encryption if data is sensitive.

join.me and teamviewer are two I use. Teamviewer if you don't want someone to have to be sitting there to "let you in", they just authorize you and you can log in any time. Great for accessing your own computer while away.

With over a decade of experience in IT, including IT Support, TeamViewer is the winner so far compared to the rest of its' competitors simply because it's way faster & you got all the remote access features needed.

I worked with many start-up IT companies and we had a lot of work with remote desktop access and their alternatives. Here is a list we used in our company, hope it helps you: https://www.g2.com/products/remote-desktop-services/competitors/alternatives
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath