Hinayana the main focus is on study of the straws.
Mahayana takes a larger scope to include other writings and practices.
Basically it's all "the path"... no matter how one looks at it. Some can say "higher" and "lower" and they'd be missing the point. Especially in terms of the Western mind, we just love "winners" and "losers" and that's not the goal. No matter what your choice, if you were to choose Buddhism as a path, it depends on your own mind and what feels right to you as a person. True Buddhist practice is all the different flavors... and that could potentially take the form of other religions too, ultimately.
Just to add to Sali's excellent answer. We tend to be too concerned with titles: Theravada, Mahayana, Vajrayana. At a teaching I attended it was stated that there is too much emphasis by some upon the tradition and lineage of our teachers. Kadyu-pa, Nyingma-pa, Gelug-pa, Palyul, Rimey, etc. are merely titles. The Dharma is the Dharma regardless so I have been told to respect all traditions. There are, however, some so-called contemporary traditions of Buddhism and "teachers" that I keep at arm's length but this is not a forum for drama bashing.
What are the differences? Mainly ritual and the texts that are studied. Some say that Theravada focuses on personal enlightenment while Mahayana (and Vajrayana is within the Mahayana tradition) emphasizes that one forgoes personal enlightenment until all other sentient beings attain enlightenment first. But, as I have been instructed, how can one lead others to enlightenment if they haven't attained enlightenment themselves?
Personally, I read the suttas, the sutras, commentaries and various texts. Some may feel that mixing teachings "muddies the waters" so to speak. But, as the saying goes, if you leave the water alone it settles out and becomes clear. Maybe that's what we Buddhists are supposed to do. So, I guess if I had to put a label on my practice I'd simply say Buddhist (smile) or is Eclectic Buddhist a bit too vague?
Not sure if this answers your question or merely adds to confusion. I sincerely hope not to the latter.
In Mahayana Buddhism,
1. they focus to reach Buddha state enlightenment
2. sometimes they pray to Boddhisattvas (a Prue-Buddha state enlightenment) like Kwan Im, some gods, and Buddhas.
3. they chant more Buddhist straws.
4. they have more religious ritual.
5. one must be a vegetarian to become a Mahayana Buddhist.
In Hinayana / Theravada (Pure Buddhism),
1. they focus to reach Arahat state enlightenment
2. they also believe in Boddhisattvas, but they don't pray to them.
3. one doesn't need to be a vegetarian, but they can be if they want to.
The Name itself is different, consequently the followers will be different ,the way will be different, the believe will be different
Like Mahayana believe Reincarnation but Hinayana does believe in that but in Rebirth.
When Buddhism was driven out of India in the 10Th Century, some of it went north, to Tibet, China, Korea, Japan etc., some of it went south, to Sri Lanka, Burma, Thailand, Cambodia. Broadly speaking, the northern (Mahayana) Buddhism entered strongly established cultures and so had to make a lot of concessions to adapt to local culture (and also climate). What went 'south' came into very weak cultures with similar climatic and economic cultures, so that the original Buddhism stayed much better in tact.
Now, there are also a good number of degeneration's from the original in those countries but they are not quite as entrenched into doctrine.
It's fairly well transmitted what the Buddha himself had to say and the translations are very readable. Have a look at setts, for example at accordionist.org
If you hear anything about praying, rituals, mantras, Bodhisattva's etc. it has nothing to do with original Buddhism but is cultural.