I'm still on Evo and still will be for some time.
I also build sites for small and some larger companys and don't need much packages that are not available for Evo and are for Rev. Its all about the speed for me, to build sites and for the client. I haven't heared and had any hacks since 1.0.15.
I don't know which one is more secure. Just keep up to date.
MODX v3 is on its way although it could take some time.
Evolution user, I like the back-end speed and simplicity
I also prefer Evo but cannot comment on Revo as I never built a full website with it.
When I played with Revo I didn't like the feel. It seemed more modern but not as nice for me to work with for small sites.
I think there is nothing you cant build with Evo, Ditto, Wayfinder and MultiTV. Its a very powerful but lightweight combination, perfect for shared hosting.
Good luck with your projects.
My opinion:
Revo - Still very much a developers tool
Evo - Very "End User" friendly
Some of my Evo clients tested the Revo UI and requested that I not convert their sites. They simply couldn't get to grips with the UI, although it is similar - to note is, those who tested are 50+ (which doesn't imply that they are to old or incompetent)
As of late Evo has been revived and major work has been completed to bring it up to modern standards
Security will always be an issue, it doesn't matter if you are using Evo or Revo - always keep up with updates and use the latest version at all times, it's that simple - it's open source and as such script kiddies will always try and find holes in the code
In my experience Revo was / is slower than Evo and in my tests it used more server resources
I started to convert to Revo, but have since canned it due to the latest updates in Evo
I work a lot faster with Evo than I do with Revo - Time is money
I haven't found anything I can't accomplish in Evo, so Revo isn't a benefit for me or my clients in any ways
