What is it you want to do with the machine? Might be that the MDF machine will be up to a lot of what you want to do. If it's practically finished then completing it & using it might be an option especially if money is tight. That way you could use the machine to generate some income for the second build. Sorry if it sounds like I keep going on about this but that was the advice given to me by some very experienced members of the forum. I know a guy that has been using an MDF book build machine for the last 9 months & although not run on a regular basis it has done everything he has asked of it so far, he is very happy with it & says it's more than payed for itself.
I was like you, started building & then discovered they weren't as good as I thought they would be so started looking into building a different machine before I had finished. After speaking to a few people on the forum I was advised it would probably be best to complete it because of the stage I was already at. That's what I am now doing, I already know it won't do everything I want it to but it will get me started a lot quicker than starting from scratch so is probably the best option.