I have never tried the inkjecta, but I have a Centri and a Dragonfly (ls).
They are two completely different machines. I use them both a lot, but i use them for different things. They both have give, but in my opinion it feels different on each machine.
I love lining with the Centri (didnt at first, but after I got used to it, its great). And I use it a lot for packing color. It's kind of big but is balanced well, so you don't really feel it. Mike's customer service is top notch.
The dragonfly lines well too. I also use it alot for grey wash. I really like having the adjustable give. It's light, well balanced, and you can buy any single part from it you need.