It’s been awhile. Haven’t tried the Gemma. Might work. Don’t recall any sparkling reviews.
I went with the SRI 420 for portability (luggable), but should have let @srihugh1 talk me out of it. It works, but is too limited to justify the price in most instances. The 310 is a better machine. I’d like to add the back flushing trick to the one I’m currently working with.
As far as hplc? I’d probably go with Agilent. Haven’t touched one in years (about to change), but they were the standard once upon a time (HP) when I did use them.
I’ve been using various models of SRI GC-FID since about 2014.