Never heard of it, never heard of it. Tekkit and Bukkit are both mods. Never heard of spout either. Again, advertising isn't really the applicable term. Unless you spend your life on a forum, these aren't going to crop up commonly.
Wow I'm suprised you haven't heard of those. Some of the first things I heard about when getting into modding MC was Bukkit, Spout, and Tekkit. Maybe you should do a little more research.
Tekkit has it's pro's. It's good for people who are not capable of modding their own clients. Also good for people who are lazy and dont want to take the time(even though it does not take that long or much effort to mod your own client). But that is about it. It has major downsides, things like mods being modified so that they will work with all of the mods in the pack and the fact it commonly uses old versions of mods. These types of actions by the tekkit team will leave you will buggy mods that are missing content.
IMO it is best to just setup a Bukkit server and mod it and your client yourself. This give you control, which if you're compentent enough is always a good thing.
I know about bukkit and I know about tekkit, but spout is a very unheard of one. I'm doing gamedev at college, practically the whole class plays minecraft and nobody has mentioned spout once. Bukkit, yes, tekkit, yes, spout, no.
It's not so much being capable of being able to mod a client, it's being able to figure out how get each mod to work. The amount of errors I've had where mods don't agree, or mods have to be installed in a certain order or forge not loading things it should or just plain going crazy and causing an exception. After all those things, to download an exe and have it just work is a huge relief. Programs are supposed to be user friendly, not file-edit crazy.
The having old stuff I can live with. Especially since newer stuff tends to sometime be horribly buggy (When I tried to run CC1.4 with the most up to date version of forge, something went odd with the textures and when I tried to place a computer, the world just crashed. I did the exact same thing with it that I did with 1.3, which runs fine.). So far on tekkit, I haven't encountered anything buggy with the mods, they've all run fine in the way they are designed to.
Possibly, but it all takes effort. Tekkit was all one download, no real instructions needed since each mod had a wiki telling you what stuff does and it runs fine, even when interacting with each other. Redpower, buildcraft and computercraft all run really well together. Not being up to date is a small price to pay for ease of use.