Over at The Ecclesia Blog, Dom Dalmasso has a really good article on the current status of the SSPX as far as its relationship with the Catholic Church goes.
Below are the major headings, along with what I think are the more interesting subheadings.
A Brief History of the SSPX
Were the Episcopal Consecrations Justified?
1. State of Necessity
2. Statements from the Magisterium
Incardination and Canonical Mission
2. Erroneous Ecclesiology
3. Validity of the Novus Ordo Missae
An important read for Catholics contemplating or actually attending SSPX Masses.
H/t Where Peter Is