I definately wanted a hardware solution for my security system, but also a bit of automation. Based on this, I chose the ELKM1G. I put in my system about 2 years ago and absolutely love it. It is very reliable, even though I had what I considered tough installation requirements from the wife.
1) Garage, main floor, finished basement, and unfinished basement each on seperate zones that can be armed and disarmed seperately.
2) Only want 1 keypad at the entry, so garage, finished basement, and unfinished basement need to arm and unarm automatically based on occupancy.
3) Need to be able to toggle on and off various features without having to remember how to use bypass functions.
4) Living room area has to be able to arm and unarm at night based on specific movement (if LR motion is detected and hallway motion was just detected, then disarm, otherwise trigger alarm).
5) Need various modes like guest, overnight guest, etc. that can be easily changed to prevent false alarms.
I ended up having to use around 35% of the ELK memory to write the rules, but they have worked great. I am currently expanding my system to allow wireless network control as well as water pump and flood monitoring (Plus a bit of rewiring due to n00bie mistakes). After that I may start looking at fun stuff to do with an automation computer and software, but will have to see. The different lighting possibilities have me a bit overwelmed.