I've had some experience with alarms, having worked in two different Canadian Monitoring stations (neither of them were TMC) and having installed alarm systems for a living.
I was well aware of the markup in alarm monitoring, and really just wanted a central station watching over my alarm system (burglary and fire). I didn't want fancy monthly/weekly reports as to activity, and didn't want the station to keep track of whether the system was armed or not.
TMC has delivered on their promise. Their technician was professional and pleasant, arrived on time and tested the system fully.
We've had a few alarms since (legitimate false alarms, mainly due to pets) and TMC has always been prompt in calling the keyholders (or in one rare case, dispatching the local police).
We moved after 11 months of service and TMC was right on the case following up on when the system would be active at the new address, ensuring that the zone list was correct and that our emergency contacts had remained the same.
Frankly their service is much better than companies that charge 2.5X the money.
I'm a satisfied customer.
Updated: 30 March, 2014 - I am still a satisfied and current customer of TMC years after writing the review above, but should note that I did recently get my monthly rate increased without explanation from the posted and highly advertised $9.99 a month to $12.99 a month (Keeping in mind that I did enjoy the $9.99 rate for 5 years) which I found a little disappointing. We do not generate many alarms and you would think that customer loyalty would be rewarded, not penalized.
Update: We've changed monitoring stations. We were able to arrange monitoring at the old $9/mo rate somewhere else.
TMC will not refund any portion of your annual fee, but will keep a "credit" on file that you can use later or transfer to another customer. Not happy with this, but frankly it's been the only disappointment (aside from the rate increase) in the time we'd been with TMC.
I'd still recommend TMC, but would warn people that they will inevitably raise your rate after a few years at the $9.99/mo level.