Each movement believes it is the best way to practice Judaism. Otherwise people would belong to a different Movement. Is one movement "better" than another? What's the "best way" to be a Jew? It depends on who you ask.
The Orthodox Movement (including Traditional Judaism) is the most traditionally linked and the main movement in Israel. Halachically it is the most strictly observant without question. However observing a completely halachically observant life in difficult, especially for those living in non-Jewish areas.
The Reform Movement, which began in the late 1800's believes that the times have changed and that Judaism must adapt if it is going to survive. The Orthodox see many reforms as assimilation that threatens our future. Several of the reforms it embraces are regarded as "heresy" by many of the Orthodox. However the Reform Movement has found wide acceptance among Diaspora Jews (i.e. those not living in Israel). It is all but unknown in Israel.
The Conservative/Masorti Movement seeks to be a balance between what it sees as two extremes. Some of these congregations lean more towards the Orthodox perspectives, while others are more to the Left/Reform. We sometimes refer to "Conserva-dox" and "Conserva-form" sects within the Conservative Movement.
The other groups, like Jewish Renewal, Reconstructionism, etc. are generally well left of center. There are also a great many "independent" and house shuls. Their nature depending on the views of their local members. Some of these are virtually Orthodox but most are closer to "Conserva-form."
Jewish Orthodoxy (Traditional Judaism) has great diversity within it. Some are Hasidic (i.e. followers of one of the many sects based on the BESHT) while others are very opposed to Chassidus (i.e. the "Misnagdim"), others are neutral on the subject. Some are so devoted to a certain rabbinic lineage that they wont even consider the other Orthodox sects to be authentic, let alone the non-Orthodox.
Orthodox Judaism, as a general statement, does not accept the legitimacy of most (if any) non-Orthodox rabbis. The non-Orthodox female rabbis have no Orthodox acceptance since Orthodoxy forbids women to hold this position (this may be about to chance but the majority will still reject them). Because of this lack of acceptance of non-Orthodox rabbis (male or female) Orthodoxy does not recognize the conversions they oversee. As a result, the vast majority of converted Jews in the US and the EU are considered Gentiles by most Orthodox Jews. In order to be accepted as Halachically Jewish such Jews must re-convert under an Orthodox beit din (i.e. religious court). I have spoken with people who have converted three, even four times seeking acceptance. Even then, Orthodoxy itself is sadly inwardly divided and not all Orthodox dinei Torah will accept conversions they did not personally oversee. This makes determining who is and who is not Jewish incredibly difficult.
Very little about Judaism is "black and white."
Having said this, for those wishing to live as strictly Torah observant Jews, and wanting to be accepted as such, one of the Orthodox sects will provide a greater level of halachic observance and guidance as well as acceptance. The Rabbinic Counsel of America can guide people into the widest levels of Orthodox acceptance and practice.
Personally, I am moved by the teachings of Rebbe Nachman of Breslov so I embrace a basic Breslover Chassidus. BUT its not for everyone. There is no one correct way to be Jew.
I believe "a Jew is Jew" and that the divisiveness between our movements is destructive and unneeded. When one determines what kind of Jew he/she wants to be, i.e. the level and method of desired observance, the rest usually become clear.
For many Jews the decision comes down to shuls in their area. Many areas that have a Jewish presence will only offer one or two choices. Often there will be a Chabad (which is an Orthodox Chassidic sect) and either a Reform or Conservative synagogue. Many areas only have one option while some will have many more.
Also, many religious Jews choose not to attend any services at all but do their observances at home. Some only go to a shul during the High Holy Days. This is not necessarily an indication of their level of observance nor devotion.
One alternative to the brick and mortar shul is making online connections such as our House of Seven Beggars (Rabbi Aryel Nachman ben Chaim), Breslov Campus, Web Yeshiva and so on.
If possible, decide what you believe and how you wish to live your Jewish life and then find a shul or rabbi or option that fits that goal. And remember, on Derech HaShem ("the Path of G-d") being static is not a virtue. As you grow in your Judaism embrace your various options.
For more on this topic see my:
Der Alte Weg
Boycott Jew Hatred!
Chicoans For Israel