I give blood regularly.  This is my go to spot.  They usually get you in with little or no wait.  I always make an appt online but have seen people come in as walk-ins and they don't seem to wait much longer then ones with an appt.  For the most part everyone is very nice.  There are a few cranky ones but I guess that is anywhere.  They usually have a promotion where you get some kind of freebie for coming in.  You get it even if you don't donate for whatever reason, low iron, etc.  I always feel guilty when I can't donate but they are really nice about it.  \n\nOnce you donate you will be on their list and they will call you to ask you to donate again.  You can let them know not to call and they will only contact via email.  I do this cause the calls can get annoying.