I have been on both sides of this issue. I have 2 kids who have both been in daycare (at earlier ages outside of my home) and now I have my own daycare business.
You don't mention the age of your son, but I would guess he might be about 2?
I think home daycare is a wonderful transition from home/nanny; au pair situations to preschool and then preschool a wonderful transition to kindergarten. The key is finding a really good, loving and stimulating environment, which can be difficult. The advantages that I see in my daycare are that children learn really valuable social skills by playing with their same age peers and also slightly older and slightly younger kids. In this process, a child learns patience, how to share, take turns, trust other adults and friends and be empathetic. They are exposed to new situations and experiences that they may not normally be able to experience. It better prepares then in a small environment to be able to cope with the same issues on a larger scale when entering preschool.
We do lots of art activities that help development of fine and gross motor skills and self esteem. We play games that involve team work and exercise. We spend lots of time outside. We sit together at meals and snack time and have conversations and practice good manners... and the list goes on...
Your little guy might cry, and that's ok, as long as you have a provider that you trust will handle things appropriately. Remember that kids act completely differently when they are away from parents and in a different environment.
I don't think 2 days a week will compound your mom-guilt. Depending on his age, I think you will both be happy with the result of him experiencing new growth!! He may cry when you drop him off, but eventually (if you get a good place) he'll cry because he doesn't want to go home!!
Best of luck!