Using different cellphone lines

There are a lot of mobile lines available in the market. Most of the big players in the telecommunication industry offers a very attractive deals. Some offers a free mobile unit for their monthly subscription while some offers a free days call whenever you buy their simpacks. I have three cellphones here one is Nokia 6510 which is my second cellphone, my Sony Erickson P800 whom my sister gave it to me because she no longer used it anymore and my latest cellphone Nokia 6630 where I bought it 2 years ago. I have decided to buy two simpacks for my two extra units to know which cellphone lines give more benefits to the users. I bought sun cell simpack, globe and smart simpacks. among the three sun cell lines is the cheapest but the problem is the availability of the reloading station is very less, you need to go to the mall where their reloading station is present. what if, the mall is closed due to some instances? so, you can't buy for a load. I have decided to stick on my original Sim and that is Globe because all my contacts are already here listed.