its funny how everyone is mixing up the government services with the companies. postal services like USPS and australia post have a gaurantee to deliver to every address. this is in government legislation. so long as you have an address mail can be delivered to, they have to deliver it. australia is a good example of what value for money that is. mail is gauranteed to be delivered every day, except remote locations which are twice a week. for 50c, i can send a letter to some po dunk little town in the middle of the desert. it cost me 50c, but to get it there would have cost hundreds, when you consider it would probably go by a contractor in an airplane.
all the companies however, dont have to gaurantee jack. it is on their interests to alert you to what they can and cant do before you do a deal with them of course. and for certain things, you have no choice. post services dont usually allow anything over 20kg or a certain cubic size. also, specialised services can do a better job with certain things, if you are willing to pay.
i've worked in the logistics of both public/private companies and government (post). i can tell you now, that in either case, it is a mistake to imagine anyone handling your precious package with kid gloves carefully placing it 'just so'. in all cases, there is no time for that (except like i say, with specialist companies. furniture removalists are normaly quite careful). all stuff will be literally be thrown from place to place during its travels. so pack it with that in mind!
honestly, i know i might be biased, but for most things its way better to just use the post. they will always have the biggest networks, the most offices, and ship every day to everywhere. with post too, if you arent home as level points out, you wont have to travel to some distant industrial zone to pick up your parcel. and if you are like me, youll have a PO box at an office thats open on saturday so you can pick it up from the counter (",)