worst parts:
it has clearly not enough vowels (3-5 vs. for example 14-15 in german)
its rhoticized vowels are a pain in the ass.
the mangling most loanwords are being subjected to is just plain horrible. acceptable would be: leaving them alone, or ending up very fucked up and cute (like in serbian).
two dictionaries, of which both are very useless when precision is a must.

best parts:
syntax that is dead easy on paper but ambiguous as hell in practice.
garden-path sentences actually work.
it's easy to break in funny ways.
300-400 years ago it was one of the most beautiful languages in europe.