What is everyones opinion on applying to unis again when you didnt get accepted the year before? Has anyone reapplied and been successful?

I applied for PhDs when i was in my fourth/final year of my undergrad but didnt get anywhere (although I came close at one place). I am now doing a MSc and will be applying to unis again Dec/Jan time... but is it worth reapplying to ones where:

I didnt get an interview last time
I got an interview last time but no luck

Will they mentally reject me because i didnt get anywhere last year? Especially those when i didnt even get an interview. Or should i try my hand at new unis?

if you have gained extra skills or msc there is no reason not to apply, that was likely to be the main reason you didnt get through last time.

You should definitely reapply! I am about to enter into my 2nd year of PhD at a university I was previously rejected from. Although when I first applied I had experience of my field outside my degree, it wasn't enough to get me the place. And I had applied and was interviewed for several other projects around the same time, so I was juggling too many balls. After graduation I managed to get even more experience and 6 months later I applied again and got it. I think once you've graduated you have a better idea of what you want from a project and where your interests lie, and I think that comes across in the interview. Don't worry about prejudice, you will simply have to tick a box on the form saying you've applied previously in 200x and they'll see that with additional experience you are now even more determined to undertake the project. Good luck!