Full Disclosure - I work for Eagle Eye Networks, cloud based VMS company - and we charge a monthly fee for our product.
Since this is our business model, take what I say with a grain of salt.
Now that all of the disclosures are out of the way, I will say that for us, this is an effective model. It doesn't work in every instance or for every customer. However, there is a lot of interest and some of our integrators are bundling the cameras, installation service, maintenance and everything else needed into a monthly price for the end use (just to be clear - Eagle Eye only provides the software/cloud service in this arrangement - the integrator is providing the rest of the services and equipment.)
The end users we've spoken to generally like this, because it is a fixed cost for them and they receive consistent service. Many businesses are moving to this model for things like email, phone service, backup/data storage, etc... so buying video surveillance this way is sometimes a natural next step.
That being said, there are still people out there that don't like paying monthly, just like there are people that don't like IP cameras.
A benefit for integrators is that they can get RMR from video, which traditionally hasn't been an option in the past. An important point that was brought up to me from one integrator is that RMR (whether it's from a cloud service or some other source such as financing) increases the value of your business, providing many benefits to the business management/ownership.
My short answer is that yes - it's a good option for many customers - but it's not for everyone or every project.