choice: module or externe app?

[mel]

Hi
I'm quite new to CMSMS and would probably continue to learn it.
I want to create a personnel project involving a big use of calendar. It will be almost ALL the web site. For now, I will be the only admin but eventually the users will be allow to post their suggested events. I'm looking for the best solution. I try the cmsms module calendar and also Webcalendar.

CMSMS:
+ only one "site" to manage (esp for database and adding/editing)
+ best incorporation in the website
+ quite simple
- miss a lot of functions I need for now


Webcalendar:
+ import/export ical format
+ rss well implemented
+ adding extra fields easily
+ categories filtering by front-end user
+ recurring events
- I dont like embed function
- very difficult to personnalise (for css, and dont have some so cute templates like cmsms)
- too much options I dont need


Before I start, I need some advice about the choice? Some suggestions, ideas? Any experience to share?
Just a precision : I cannot change any code I dont understand enough for it!

Thanks a lot!
Mel