so I have an opportunity to buy used Mackie CR4 or used Presonus Eris 3.5 at a low price. Price of both is almost the same, so I really can't decide which one should I get. They'll be used mostly for mixing. Help?
They are probably killer computer speakers, but I would be afraid you would run into problems getting your mixes to translate to other people's stereos, being so small. I would wait until you can get something larger. If there's one piece of equipment to splurge on, in a studio, it is monitors. I'd be more confident mixing in mono, on one normal size monitor, and using headphones for the stereophonic decisions, then relying on little monitors to tell the whole truth.
I actually have those Presonus ones as ‘decent home stereo’ reference monitors. Always find it is best to check near final masters and mixes on a few systems ranging from great to horrible. They are not as full and flat as the 5 inch or whatever Mackies I have, but seem consistent with lol your typical $1000 home entertainment center setups I’ve compared with friends home systems, okay a little flatter.