what are the advantages of having a distribution block as opposed to say... a wire nut with one wire to battery and one wire to each amp connected in it?
Getting a good solder joint in large multi-strand wire is really a pain. Cold solder joints are usually what you end up with and they vibrate loose. If you do manage to get a good solder joint, you will have to undo/redo it if you make any changes to the system. You also have to make sure it is insulated and will stay that way (electrical tape will break down in the car and is not going to cut it for this). You can get an inexpensive ditro block from Wal-Mart or off eBay for around $10 maybe even less. It will save you a lot of time and effort and will be worth the money.