Ok, well IO dont know if NewBook offer service in Kenya although being cloud based it shouldn’t be that hard for them but I would recommend them based on our experience so far.
SambaPOS is far from being capable of being a ‘Good’ PMS system especially for a large hotel.
For a small place you could get away with it doing manual bookings or using small online system and using SambaPOS as the on site ‘in house’ guests system but it would take allot of work to even come close to being a actual booking system.
The offline/samba only topic I guess your actually refering to would be doable even for larger hotel and with dev could definatly be made better but you would really be better off with a real PMS system with than many rooms.
Since you dont have an existing system if I were you I would choose one with an API they are open to allowing access to - check it has required requests and butcher my PMS intergration scripts to work for that PMS.