I have previously used Chamexpress without a problem, but Alpybus times fitted in better were slightly cheaper and seemed to be a decent company, despite mixed reviews. I would steer clear of them at busy times ie: Saturdays or School holidays, as our experience was not good. However our friends who travelled with them Sunday to Thursday had no problems.
We travelled Feb half term and arrived in Geneva for our departure with Alpy at 19.15hrs. I spoke to the rep who said that we would be leaving at 20.00hrs which was slightly disappointing but went with it. At 20.15hrs we were still not looking like leaving the arrivals hall so after asking the rep again he informed us that we were waiting for the 20.00hrs flight from Edinburgh. None of these flights were delayed, the bus was in the carpark and all the horrendous traffic jams of earlier in the day had gone, so it was obvious from the start that they were waiting to fill the 8 seater minibus no matter how long we had to wait. This was eventually 1 3/4hrs as we left just gone 21.00hrs! The third party driver they sub-contracted was English and was very apologetic although obviously not his fault. On our return we had a text to say that due to the proposed traffic problems getting back to Geneva on our return they would pick us up 20 mins earlier than arranged. We stood out in the cold for an hour after various phone calls to the rep at the airport who said the driver was delayed. I voiced my concerns over the fact that we may now miss our flight and the rep said it wouldnt take us long to get back to Geneva (despite all the traffic warnings??) The journey back into Geneva took 2 1/2hrs and after pleading with the check in staff we made it onto the flight with 2mins to spare! This was obviously very stressful and totally unncessary. This company has knowledge of these busy periods, and seemed totally unprepared or uninterested in getting us back to Geneva on time. I have emailed my complaint without reply, and feel that the rep was totally disingenuous with his information.
My advice use them if you want but be prepared! They advertise a timetabled service which seems to be pot luck.