My daughter received her invitation to Gemstone last night.
So did mine. Since my DD is studying engineering she may have to rethink Gemstone and go into general Honors.
She could start out in Gemstone and see how she likes it. You can drop out at any time and go into University Honors. My older daughter (Senior) is in Gemstone and loves it.
That is why she chose Gemstone because out of all the specific programs that is the one she liked the best, What is your oldest daughter’s major?
DS invited to Gemstone. He wants to be a part of the Virtus (male engineering students) LLC. I don’t know how this is going to work. Can one decline being in the Honors College?
My daughter is a neurobiology and physiology major. She really wanted to do integrated life sciences, but she received a 4 on her AP Bio test. Now it’s possible to participate in ILS with that score. So her first choice was Gemstone. She met her boyfriend, who is also in the same program. They are on different teams. She would tell you she is happy that she picked Gemstone for that reason. 
One thing to note for those who want to go to graduate school, the depth of research from Gemstone does not really satisfy the level of research they are looking for. It would be a good idea to also participate in more in-depth research.
@MDdad2012 thank you for that information. I’m surprised about your comment on the research from Gemstone not meeting the expectations of graduate school. How is it possible to participate in more in-depth research while at UMD? Do you have to contact individual professors? Or do you have to make a research proposal within Gemstone that is more in depth than the general choices?
@ReminiscingDad - I also agree with @MDdad2012. When my kid graduated, Gem project was the last bullet on his graduate school applications/resume. I think Gemstone “teaches” kids how to do research but the depth of research itself may not be at the level of “pure research” work conducted by likes of NIH, NIST, or any of the national Labs. It is, nevertheless, very valuable lesson if your DC is interested in research in grad school or in professional life. As for participating in more in-depth research, your DC can find a professor and work with the professor (usually starting in Soph year) or find an outside internship. Hope this answers your questions.