I haven't read Finn's book yet, but when I took Theoretical Mechanics (upper level of Classical Mechanics) course, my exercises-teacher (different from theory-teacher) told us to read and do exercises in Landau, Calkin and Finn's book, because they were very good books, but I just read Landau on theory class and did exercises in Calkin and Goldstein book, didn't have enough time to read Finn. So, just give it a try if you have enough time, the more that you read, the more things you will know ^^
And I see that you've asked about Lagrangian and Hamiltonian, that's Theoretical Mechanics. For Theoretical Mechanics, I recommend you to read some books (just recommend, it depends on you, your teacher, and maybe members in this 4rum):
1. Landau, one of the most famous book in this field. Concise, sometimes you will scratch your head all day long because you don't know why he could have this result.



Then your teacher comes up and everything will be ok

2. Goldstein. For me, it's easier than Landau, but still hard, need time and effort.
3. Walter Greiner. He has written a lot of books from classical to modern, and he has written 2 books about classical mechanics, but I recommend you to read the one called
Classical Mechanics: Systems of Particles and Hamiltonian Dynamics
4.
Lagrangian and Hamiltonian Mechanics by M.G.Calkin. Nice and well-written book, most of my exercises were taken from this book
5.
Analytical Mechanics by Hand & Finch. For me it's well-written too, but I see that it is not appreciated on Amazon
6. V.I.Arnold. It's hard for me but it will be ok if you have a very good mathematical background.



Whatever books you read, you still need to spend a lot of time and effort.
Good luck and try your best
