Personally, I don't like Chamsys. It locks you to their hardware, and while the DMX interface looks cheap, you need to pay €€€ for future expansion (for example, if you want to use your own midi controller, you need a ridiculously expensive MIDI interface as the program will only work with that). Alternatively, you can go with their wings, but I don't like them (personal preference of course). They are a bit limited. Other than that, the program feels slow, and not intuitive.
I have to nuance my statement by saying that I only had one encounter with Chamsys which wasn't very great. It was at a venue where everything was preprogrammed and all I could do was pick a chase and dim the lights. Even tap sync wasn't working. I was very unimpressed.
Other than that, it looked powerful and feature rich.
Perhaps Norty can comment on the ability of the program to sync with other programs. I think it's mainly a live program, but I didn't bother finding out if it has a timeline :P
I don't know how you see it. In Freestyler, you create a chase with preset values, which you can put in a cue list and play back. You can select which chase to play and speed (tap sync) using MIDI. There's no timeline. The way to go would be to send midi signals from LSX/QS through a virtual port that trigger chases etc.