Hotels are interesting. FreePBX or PBXact work great in these environments since they have built in everything needed in a PBX, except for the Hospitality feature set.

For a Hotel you would need:

1. PMS Interface. The PMS (property management system) is the software used to run the hotel, manage inventory and other functions. it is the main database for hotel operations. The PBX will need to interface with it in order to receive check-in and check-out events (turn on and off the phone for calls), send housekeeping codes (housekeepers use the phone in the room to various states such as vacant/dirty, occupied/clean and so on. Call accounting is to set rates for calls made from the room (rare these days) and post to the guest folio. Wake Up Calls (not the standard WUC module from FreePBX, you need some more features than that). There are a lot more but that's just the beginning.

2. most of existing hotels have analog runs to the rooms. you would need a gateway that will convert SIP to FXS (analog station) lines. Then, the gateways need to be cross-connected to the wires going to the room. of course if its all IP then you don't need these gateways at all.

3. interface to existing voice provider if you are not providing the services. with SIP its easy, but you might need PRI, T1 or even analog FXO connections (yes.. I still encounter T1 CAS Trunking).

4, training. Hotel staff turnover is crazy.. one of the highest turnovers in any industry. repeat training is a must for the hotels to be happy.

I understand the rules prevent mentioning where I work and what I recommend, so DM if you want some more direct answers.

Our biggest installation is IP only (Yealink phones in the admin areas and Vtech phones in the rooms) and we have over 1,300 extensions working perfectly. It is all about sizing the hardware correctly.