I only want to know if the quality is better or to compare with the C1 and is not like a office machine.
Not exactly earth-shattering advice, but I'd get print samples first and judge with your own eyes. Have samples run on a couple different stocks and from your file that represents both a standard and the most difficult thing you or the user will usually print.
To my eye, the C1 has slightly more natural flat on uncoated stock and slightly, slightly more even gloss. However, I've been very pleased with my 242's prints on both bond and especially on coated sterling ultragloss, hammermill color copy gloss, and on 8 and 10 pt kromekote (and it's ok on 12pt kromekote.)
On uncoated bond, for some jobs I slightly prefer the satin toner of my previous canons. On others, I actually like the glossiness of the 242's toner in normal mode - not a ton, but somewhat glossier. I like the black-black, the gray tonality, and the overall print quality. And I like the flexibility of it's enhanced gloss mode. The gloss level isn't 100% perfect; on heavier stocks like 12pt, there is a slight, what some have described, as a baked-on look if viewed from an angle. But my customers have been very pleased to date and I don't mind it. If I was comparing the two side by side, I'd give the C1 the nudge on finish evenness. But with everything considered - speed, cost per print, and robustness, I'm 100% happy with my choice to get the 242 with the OHCF.
Right now the meter is at 865,000 11x17 and 12x18 prints on ours. Ours has required the ITB cleaning blade to be replaced twice, the ITB belt to be replaced twice (easy), the black developer twice (easy), a duplex assembly once (easy), and at 850,000 had the first major issue which was a streak in the ROS assembly (a fairly lengthy repair). All in all, maintenance required has been extremely low compared to any other printer I've had. I think the engineering of the drums, toners, easily drop-in fuser, etc. etc. is well done to create a very efficient-to-operate machine. We put noticably more maintenance time/money into our previous canon machines. All in all I'd give our 242 10 out of 10 so far. No regrets.