Squidoo is generally better then Hubpages for promoting your site and yes the links from Squidoo will be good for your site's seo.
Squidoo and Hubpages allow you to commit to it without spending any money or troubling yourself with designing your own site. They also allow you to try different affiliate programs to see which work best for you. I say start at one or both of them and then, once you've found a couple good niches, then make your own site for the niche.
Well Squidoo can be as supporting platform to your main website. Comparing own domain and squidoo is not at all justified. Squidoo, hub pages, Blogspot and other web 2.0 properties can be used as quality and relevant link building. So if you have your own domain than you should have one squidoo lens for each domain and your niche. But you should hire a professional squidoo lens builder who knows everything and how squidoo works.
I love, love , love Squidoo! Once I got the hang of how to use them ( and yes, I did buy a program to help me with it called the One Week Marketing which you will find all over my sites listed below, as it is one of my favorites) I started seeing results within a few weeks... more traffic to my websites ( I link them to my sites) and more $ ( traffic equals $$)