both celcom & altel got their own 4G network .. but both line not cover up the whole area.
so in a place where there is is no altel 4G line, so can use celcom & vice versa.
this is smart partnership that can save cost a lot.

Used Altel on my secondary phones and mom's phone. Good coverage and internet speed so far.

Pro:
-Can get long validity. First single topup rm50 after registered get 1 year. Additional year can buy at RM28/y
-1GB and 2GB plan has 90 days validity. Good for mom and makcik who only know use whatsapp.
-Top up rm30 get 300MB and top up rm50 get 500mb data.
-Lots of number cantik. Mine for eg is 011XXXX0001. I gave my mom with ending 8.

Cons:
-Inside building may have signal issue. Anyway that apply to all telco which did not have signal booster in building.
-No itemized bill (so far that I know). Their website did not have this.