I ported my prepaid number from Swisscom to M-Budget.
Received written confirmation and SMS that this would be ported on 28.12.2017 08.00.
My number was 'dead' at around 08.00 on 28.12.2017.
When at about 16.00, 8 hours later line still dead, I call the service center. Answer: We have problems....we'll take care of it....
Now it's almost 7 p.m. and the line is still dead and the service hotline is closed.

Dear Community users
The never-ending story of this number porting is now complete.
After 13 working days !, the number could finally be ported yesterday 16.1.2018 at 16.08 hrs.
Kathrin from Migipedia supported me as much as possible.
On a positive note, I received a credit note of CHF 50 for annoyances, delays, etc..

It's up to you to decide whether it's worth switching to M-Budget-Mobile with such hassle and annoyance?