I did HSK level 5 in December. For me it wasn't very hard, mostly because I studied the language for one year, and have been in the country for years now. But I can say speed is the biggest challenge, you have to do 45 reading questions in 40 minutes, and 10 writing questions in 40 minutes too. About preparation, I used this book 新汉语水平考试模拟试题集HSK5 and it was very helpful, I highly recommend it. It contains sample tests that are identical to the real test.

Speaking of writing, I think it is the most difficult part of the three parts (listening, reading. writing), and it was the part that I scored least. The total score is 300 and you must get at least 180 marks to pass, but the easy thing is that it is not compulsory to pass in each part, so if your writing is not very good, you can make up for that by trying to score high in listening and reading, so that you can reach the pass mark of 180/

I know I'll get thumbed down for not answering the question but BIG respect to you both.  Not easy.

HSK is not easy for foreigner to get pass unless you paid a lot of effort on it. Now in some China universities. If you wanna passed your year 1 and year 2 before going to Year 3 and year 4. You at least must passed HSK level 3 and 4. If any foreigner do have the issue on HSK test can drop an email tovince@dimm2h.com. We provide one stop service to solve your issue to get promote in your university. 

I am also planning to go for it.. but definitely not level 5..

Help will be appreciated