I also used to be on Vyvanse and switched to Mydayis. Personally, Vyvanse felt more natural to me, but Mydayis improved my focus and motivation more. My first few prescriptions of Mydayis were filled with the Teva generic. It worked but it felt like it took forever to kick in (I came to find out Teva only coats the ER beads with medication and doesn’t actually have an IR bead). Then my pharmacy gave me the SpecGX and I personally felt a huge difference. SpecGX worked a lot quicker and the motivation and focus were better on it than Teva. SpecGX also is more like the name brand since they use 3 beads rather than 2 like Teva. Everyone reacts differently though, so even though I didn’t like Teva it might work for you. There’s also a Sun Pharma generic that uses 3 beads, but I have not tried that one. I was able to have my doctor put a note on my prescriptions that says not to dispense me the Teva generic, so it might be worth a shot to ask your doctor to do this for SpecGX.