Does RS have a favorite ATM company to use and does he have a favorite company for a SIM card?
No, he doesn't have a "favorite" ATM, and neither does any one else. You should avoid ATM's that are not from banks, such as Travelex and Euronet. Otherwise, any bank-affiliated ATM is fine. Just avoid "dynamic currency conversion," which is when the ATM, credit card machine, etc., offers to process your transaction in your home currency. Always have the transaction processed in Swiss franks, and decline any offer to "lock in a rate" or however it may be phrased (this almost caught me at the ATM in the Zurich airport, until I realized it was actually DCC).
As for SIM cards, you have to do the research, as the deals change all the time, and it depends on what you are using your phone for - calls within Switzerland, calls to EU countries, calls to other countries, texts, data, etc. Remember that since Switzerland is not in the EU, it is not bound by EU rules on phone rates when roaming.
The Prepaid GSM website has a good forum where these issues are discussed. But be aware discussions can get very technical, so don't be afraid to ask for clarification. http://www.prepaidgsm.net/forum/forumdisplay.php?s=f370f4c513c799dbead864677c9bf569&f=36
If you to research deals yourself, here's their page of Swiss prepaid GSM operators: http://www.prepaidgsm.net/en/switzerland.php