Employees and "customers" are highly distributed. There are lots of SaaS providers already in this space. The user base is much less elastic than other SaaS markets but the advantages in system administration and client admin should overcome the lack of savings there. I do think this is ripe at the moment because of pricing pressures. Processes are more complicated than simple service businesses or Restaurants but still, not that bad. And the budget pressures in this space might encourage folks to give up on PSFT and other rich apps they spent lots of $ for 8-10 years ago just to get rid of the maintenance costs.
Micros, a restaurant sw leader, already offers SaaS. It's really a matter of someone moving this downstream. iPhones + iPads and nothing else could be very disruptive here - the processes are pretty plain vanilla. Square is certainly going after the smallest end of this and could move up. Sales + marketing costs to this field are painful and if you already own Micros or a competitor, why move? Well, if you plan on growing, you can drive down POS device costs a lot.
However, around here the medical groups have already done this in a de-facto manner. But again, the tablet, mobile nature of the users, might enable a breakthrough here. Not as likely as restaurants though. The insurance piece alone might enable disruption as things change around in 2014.
Just like restaurants. However, there have been a number of failed startups here. Again, if you are up and running, why move? Not a hard infrastructure to administer on the back-end. The major chains are de-facto SaaS providers but lots + lots of hotels are not affiliated.
Again we see square being disruptive but the processes are simple enough there will be lots of players.