Where are these Celcom Wifi locations?

Actually, can just call the respective call centres (123, 1111 or their fixed line numbers) to enquire, don't have to physically go. But the SOP is Celcom submits porting request to Maxis, and then Maxis processes. You should get this sequence of sms:

a) Celcom thanks you for choosing them.
b) Maxis asks you to confirm the porting request by answering Y or N.
c) You then get an sms from Celcom saying either the porting is approved and wait for activation, or saying your port request has been rejected by Maxis.
d) If successful, no more sms, but your Maxis line will just die, then you replace the sim.

If you don't get (a) then you need to check with Celcom. (b), with Maxis. © with Celcom. At any point, you may be asked to call Celcom to resubmit your application and restart the whole process.

I ported 4 lines, 2 went thru the next day, 1 took a week, the last one 9 days and 3 rounds of resubmission!

I prefer to pay rm38 for (3+3) GB of data and pay a bit more for voice calls (don't call much) and sms (hello, whatsapp?) rather than rm128 for only 2GB data and unlimited voice plus sms. Don't think I will ever spend rm90 on those calls and texts.

That's true, some are finding that the urban (esp indoor) coverage is not as good as Maxis in some locations. But overall, it's still by far the best deal available...

Well, I'm swinging my 4 lines back to Maxis. Celcom service coverage and quality both voice and data are atrocious! No service inside my house and office, many times h+ or 4g outside but websites don't load...
No wonder I don't finish my 3gb each month!