I'm also loving all the new / old effects being added, things like the RF SIO emulation is seriously great, it adds so much to the feeling of the emulator for someone who has used the real hardware for a long period of time. Visually the quirky artifacting is also really loved by myself because that's how I remember it, I didn't have a wonderful S-Video mod etc, I just had RF initially and then composite so these funky artifacts really do add to the experience. Sure.it must be lovely for people using WP's etc to be able to read the text super clearly but I'm just an old school gamer / cheap hacker.
Maybe emulate a layer of dust on the screen where you didn't wipe it down for a while because you were too busy playing
(Twas a joke)
Altirra gives something to all of us no matter what you do on the system.