My opinion is that Altiris is an interesting product yet patch based, that is, useful products have been bundled together and for less sofisticated users or small environments may be an interesting choice. Yet one notices the problems that derive from patching different products together.
Marimba is more powerful yet lighter on resources usage: CPU, network, etc. Due to its 100% Java based technology everything seems possible and doable with very little effort or knowledge. It's a one product dedicated to one functionality. Other functionalities they leave it to other focused software suppliers. They have unique features such as byte level differentiating, firewall trespassing and others.
SMS is Microsoft. Simple and that's it. If you won't push it it may work.