Incomparable Prepaid mobile plans
I noticed a trend in Singapore and Malaysia, where mobile operators make it incredibly complex to maintain connectivity without a contract.

Why? For a higher ARPU! I predict this unscrupulous business strategy will bite operators when they want to become banks, see DASH.
Consider a typical 2GB prepaid offer that Hotlink (Maxis) sell in Malaysia:
- Depends on whether you bought the older/regular Hotlink SIM card 10MYR or the new "Hotlink Fast 4G" for 15MYR (both do 4G, but plans are different)
- Only valid for 2 weeks
- You have to maintain call credit
- You get 1GB of 4G "FAST" Internet
- You get 1GB of 3G "slow" Internet
Sidenote: speculated that what happens when you run out of 3G bandwidth in a 3G zone?
Then there are other factors. Hotlink give you better deals if you have their adware App installed. Or if you collect loyalty points.
Of course operators have different levels of coverage which are very difficult to gauge. In Singapore, you can pretty much expect blanket coverage from the major players but in Malaysia Celcom has good "country" coverage so the rumour goes, whilst Maxis is better in the city.
Then you have to consider their network and bandwidth they are providing from particular locations. I measured it and I was surprised. But Celcom I've found sometimes gives me "No service" in PJ, so WTF?! Reliability is another factor which is difficult to measure.
Of course I haven't it begun to wade through the complexity of call costs & SMS. In Singapore they charge you for incoming calls!
Best attempt to compare mobile plans I've seen in Malaysia: https://www.savemoney.my/technology/cheapest-prepaid-plans-comparison-of-prepaid-plans-in-malaysia/
In Singapore, I recommend you go post paid with the 25SGD SIM only plan at time of writing. Prepaid in Singapore is just way too difficult.
Sidenote: Do NOT ROAM WITH YOUR SINGAPORE SIM CARD. For example Starhub charge 19SGD per day for data in Malaysia, where it typically costs 1SGD. Don't get ripped off!