Although ideally I would go for a regular toilet if at all possible, I have had a sanitary unit in the loft bathroom for over 20 years without too many problems. In that time I had to have the unit replaced once and repaired twice, due to guests putting cotton wool, dental floss etc down. The engineer who repaired it first time told me to clean it once a month as follows and this will prevent it smelling bad. To clean, loosen the fuse on the wall beside the unit or if it has a switch then switch it off. Pour a litre of thin bleach into the toilet bowl (thin bleach is non foaming so is best as too much foam will clog the narrow pipes). Then flush the toilet and as the saniflo unit is switched off the water and bleach will remain in the unit and clean it out. Leave for several hours or all day and then put fuse back or switch unit on again and flush a few times. This works well and as mine is a saniplus which also drains water from the shower and handbasin I usually put some thin bleach down the plug holes of basin and shower too.