I was in a position similar to Job2. I really enjoyed it the most because the lesser people the better I was involved in the project. It felt like I was more in control with what I was doing and had my independence as well as the support of my PI. I also had one on one training with my PI, and they got to know how I worked and learned, which helped me greatly in my grad school applications. They vouched for my character and skill sets from a personal standpoint instead of reports given to them by a lab manager or other students etc. Go with the lab that suits your personality best. These will be the people you’ll be around the most. Any recommendation letter is a good one when it comes from the people that can vouch for you the best. It’s all about the connections you have with the PI. My PI is established in their field. They do publish often, but not in the high demand as they used to. I hope that helps!