Canon RF vs SLR

[ogrec]

I own a Canon QL17, which i used only to check that it works, but nothing else. I've decided i wanna try film photography and this should prolly be good for a start. From what i found on web, lens that this rangefinder has is supposed to be pretty good, even wide open (its 45mm f/1.7 btw).
But if i really do get into this film thing, slr will probably be a better option, if i get one with EF mount. Only EF lens i currently own is 50mm f/1.4 and i'm guessing it should be better then the one on RF, but then 45mm is closer to normal lense then 50mm is... and i always preferred a wider lens.
Thing is in my upgrade plan next lens is sigma 10mm which is again EF-s lens so i'll be stuck with 50mm on slr for a long time.

Would you keep this rangefinder in my place, or would you sell it and wait for a good opportunity to buy eos elan-IIe or something similar?

Btw heres a few pictures and a few specs, i think it looks kinda cool
http://imgur.com/a/NELx0#0
shutter priority AE
shutter speed 1/4 to 1/500, bulb is also mode available
it needs a 1.3V mercury battery which aren't produced anymore, but zink-air battery can be ordered from ebay and used as replacement