I am not really conversant with the Mustang 1 , but I have a Mustang 2 that I usually pull out about once a year . The reverb is usable , not great , but usable . Without knowing what styles you are into , I would suggest some type of delay or modulation . With a delay pedal you can set the time and number of repeats a whole lot better than you can with built in effects . As for modulation , there is a wide variety of choices and finally it's all up to you . Go to your local store and noodle around , it'll probably give them a pain in the butt , but it's your money and they want it. I'm not into flogging particular brands and I have no idea what your budget is , but the Marshall regenerator is a reasonably priced unit . It has a tremolo , flanger , 2 types of phaser and a chorus all in the same pedal . Again , not great , but usable and probably give you a bit more choice until you find the sound you are looking for without the expense of buying individual pedals . As for delay , I use a TC Electronic Flashback , it's rather pricey and again the choice is finally yours . There is a wide range out there at budget prices , depends on what you want , Hope this helps , May the journey be as enjoyable as the destination.