Regarding Agencies, as has been said, SOME are godawful users and abusers. But you won’t know until you try, unfortunately. If you want experience then sign up to as many as you can find. Do NOT be afraid to say no, though.
Hourly rate not what you want? Say no.
Too far to travel for the job? Say no.
Don’t feel like getting out of bed that day? Say no.
You will find one of two things. They won’t call, or they WILL call with better jobs, pay, locations. Just gotta get signed up and try it out.
Temp/Perm is where the Agency has an ongoing contract with a firm and you may get a chance to transfer from Agency to the firm on a full time basis. This has its pros and cons.
Me, on a temp/perm job, 7 months and counting.
Pro:
Can take days off as and when I want
Can book any holidays I want and be confident that I can get the time off.
Can work on my days off with another firm.
Cons:
Not guaranteed ANY work at all! We had a 2 month period of doing just 2 days a week.
Never knowing where your next shift is coming from.
Working on a day to day basis.
But some people like the Agency work
Good luck