I shadowed for about 6 months and have been an RDA for about 2 months and let me tell you, I LOVE being an assistant. Now its not all blissful because I had to take a pay cut but I am learning so much more than when I shadowed and I feel that the dentists I work for will give me much more meaningful LOR.
I get to assist with instruments, take impressions, coronal polishing, take xrays, create temporary crowns, and sterilize. In my case I get to ask the doctors whatever I want and get to ask them about the business side of things because they know I want to be a dentist.
Downsides are that majority of offices want you to be certified and the certification process is not cheap. There are a lot of nonsense RDA schools that are 6 months long and cost upwards of 10k. The one I went to was 12 weeks (3 months) and cost 3.5k but I was willing to bite the bullet.
Also right out of school do not expect to make very much, like I said I took a sizeable pay cut but then again I am 22 and have no significant bills.
Also If you get certified and start working you can guarantee that you will be working until next summer which is when you would start school so one year isnt a bad investment for them to make.
If nothing else, shadowing is still great and theres nothing wrong with getting more hours but its just less hands on.