Addons generally don't fight with each other. They all go through a fairly strenuous review process which, while it is not perfect, ensures that an addon does what it says on the tin at the time it is first released with the current version of c5.

Many of us who do reviewing for the prb (peer review board) have specific c5 installations for testing that all new addons are added to. I have one prb test site with 130 different addons installed, many pre release copies and no big compatibility issues.

Each addon has its own database table(s) and sticks to them.

Sometimes addons' css can get into a fight, but it is rare and usually easy to resolve.

Another area for occasional conflict is where some addons make extensive use of attributes. Sometimes you will find that addon A and addon B both create an attribute with the same name and use it in slightly different ways. This is very rare because most addons developers add a namespace prefix to anything like that.

You can also get issues if you use multiple addons that do the same thing on the same page. That isn't something you are likely to run into, but it is something I come across with my prb testing.

If in doubt, question a developer by PM before purchasing. That is also a good way of checking how responsive support for the addon will be after you buy. If someone doesn't respond to questions when you are about to give them money, you can be pretty sure they won't respond later.

The best way to avoid all risk is to use a development or staging site to try out addons and ideas before you then implement them on the actual site. That way you never put the actual site at risk.

This howto describes a process for core upgrades, but the strategy also applies to any major changes.
http://www.concrete5.org/documentation/how-tos/developers/organise-...

Any addon licence is for one live site and whatever dev and staging sites you use to create that one live site.

For extensibility, an easy way to stay flexible is to use c5 page objects as your data objects and attributes as your data items. (See this recent thread http://www.concrete5.org/community/forums/customizing_c5/recordset-... ). That way, you can use any addon that deals with pages to filter/list/manage the pages and hence manage your data.

Such a strategy is not always possible (and for massive data sets with many attributes, may not be practical), but is always an easy starting point.

My Magic Data suite of addons can be used to do all sorts of cool stuff pulling data from pages (and other places) and their attributes. Or, if you have a custom set of database tables, is easy to extend through its own plugin architecture to query such custom data tables.

Thank you for your informative answer.

Right now I have at least five or six different systems to perform various activities, which has been a real nightmare in herding information. Kind of like herding cats. I need to streamline the various activities, which is going to take a while.....

Your systems appear to be what I was looking for as far as CMS. It'd be nice to work with just one developer as much as possible.

Right now I'm creating the relational databases, recreating the Website, and incorporating Office 365/Sharepoint.

I have a lot of data to manipulate in various different ways.

With all the things that I can accomplish with Grandeur/add-ons, I'm starting to wonder whether I even need Sharepoint. (Not finding any info on whether I can maintain a "commercial" database within C5 just yet.)

I need an intranet and extranet. Sharepoint's extranet leaves much to be desired. Too bad what MS did to Groove. I need the database to accommodate internal and external users.

How much would your systems be able to assist with those needs?