I am in the process of deciding on an LSAT prep class. I would like to
know what my options are for online LSAT prep programs. I would like
the 5 most popular options compared using the following questions: How
long they take, How much they cost, and what the major differences
are.

I can't advise on the prep classes, but what worked (well) for me was
to get a couple of the prep books (Princeton was one of them), to pay
close attention to the instructions, and to work the problems.  The
instructions and the practice can help a lot.

Some follow-up advice: once you've been admitted to a law school,
think about taking a commercial course on taking law-school exams. 
Even if you did very well in earlier academic work, law-school exams
can be a real problem.  The format expectations are very specific, and
some of us didn't quite grasp them until preparing for the bar exam
(after graduating with mediocre grades).  I had read some self-help
books on writing a law-school exam essay, but it didn't click until
AFTER three years of law school.  I later bought the Loew's prep
materials for a friend and wished that I had taken theirs or a similar
course.

I do not have any connection with any related publisher or prep company.

Princeton Review is the best choice for LSAT preparation hands down.  

Personally, I just bought their book and worked through it and ended
up with a 172 (although I have an extremely high IQ).  I didn't
actually take the course.  The other books I purchased and/or reviewed
didn't have good explanations of the games section.

As for lawschool exams, there is a short book by a Professor named
Whitebread which will give you all of the format and method
requirements that are needed in a concise manner.  I strongly suggest
it.

Well, I can't rank the top 5, but I've taught LSAT for Kaplan for 2
years, and their course is pretty good.  That is, it's good depending
on the teacher.  The book lays everything out in the precise manner
you should do it, but I've noticed that other teachers tend to stray
so far from the material as to render the book's advice completely
inaffective.

Take logic games for example.  There is ONE sketch that will solve
perfectly and neatly more than 90% of logic games.  And will solve the
games in the space available in the margins of your test book.

But I see so many teachers doing these half-assed sketches that look
great on a dry-erase board, but would be impossible to reproduce in
the margins of the test book.  Usually because they're too large.

I will note, however, that Kaplan is good for one reason: you get
access to all 51 released prep tests.  That is, there are only 51
LSATs that have ever been released.  EVER.  And they give you a copy
of ALL of them.  And also break them down by question type.  Bought
seperately, they'd cost about $200.  The class itself costs $1300, and
includes all the materials.

Not to shill for Kaplan however.  I like my job, but honestly, they
have plenty of good teachers and plenty of truly awful ones too.

Same for Princeton Review.

And having done both, I think Princeton's methods are a little dicey. 
Unrealistic to test conditions and not conducive to the type of manner
thinking necessary for the LSAT.

cheers,
Richard

And, yes, I used Kaplan.  And I took the LSAT for real 4 times.  And I
got 170+ every time.