Hey wil.
Any of the denominations are accepting of converts. Matrilineal descent is the way Judaism is generally passed on from one generation to the next, but in Reform and I believe also Reconstructionist Judaism, it can be passed on via the father (patrilineal descent) if the child has a Jewish upbringing.
There are a few small and significant issues that separate C, O, and Ref. One is authority. In O, when you have an issue of halachah (Jewish law) that needs resolution, you go to your rabbi, who then bases his answer on previous answers given by rabbis and his own experience. If you go to C,you go to your rabbi, and if it's an unoriginal question, they give you the answer that a special group of rabbis who answers this type of question comes up with, while if it's and original question, they submit it to that group for review, and those rabbis consult what other rabbis in the past have said as well as looking at changes in situation. If you're Ref, then you may consult your rabbi, but the focus is on personal autonomy, and if something doesn't work for you, it doesn't work. For Recon there's also an emphasis on personal autonomy, but also on community standards. So what your particular community thinks, maybe you're to one extreme of it or the other, but somehow at least it's forming a cohesive whole.
Now for O, generally only traditional methods of study and approach to the text are acceptable. For all of the others, modern methods are acceptable.
For O, God gave the Torah and oral Torah at sinai. For Ref, both are human creations, first the Torah created and then the oral Torah, although there may or may not have been divine influence. For C, it could really go either way depending on the individual's inclination, although if it's more towards O, it's probably taken more metaphorically.
Theology besides these issues (unless I'm leaving something out) is generally interchangeable between denominations. Rationalism vs mysticism, etc. The only denomination with a clear theological break is Reconstructionism, although it too can reflect the full spectrum of theological ideas found in the rest of Judaism, just within a naturalistic vs supernaturalistic worldview.
Other ideas that distinguish Recon: Tradition gets a vote, but not a veto. Judaism is an "evolving religious civilization." More willing to make subtle changes to the liturgy to reflect Reconstructionist beliefs (other denominations tend not to change the liturgy much at all.)
Renewal is a transdenominational mystical movement that seeks to reinvigorate Judaism. It was started in the 60s by a bunch of hippies and some hasidim who were shedding some of their traditional thinking, incorporating feminism, hasidism, syncretism, and generally progressive thinking.
Orthodoxy can be divided up further in many different ways. One of the sub-groups of Orthodoxy is the hasidim. There are actually multiple hasidic groups, and each branch of hasidism understands it in their own way, although there are some general ideas common to hasidism. It's a mystical movement that was attempting to bring mysticism to the people. It often embraces panentheism and rejects asceticism, and separates itself from previous mystical emphasis on more complicated practices and meditational gymnastics in favor of simple ways of connecting to God. Although it was originally a very progressive group, it is now one of the most orthodox.
Dauer