The sileo looks like it has a front and rear fan, so that would be better, should be quieter too.
The Sileo is geared towards noise suppression, but that comes at the detriment of ventilation with the case lacking the usual side and top ventilation holes - which is why other cases of the same price range offer better cooling performance.
Since the 33x series is half the price and seems to be considered an all-round good “entry level” case, I figured that for my needs I’d be happy with the Sileo as long as it has at least comparable cooling to the 33x. Couldn’t find any online comparisons between them, though.
You may also want to checkout the Antec 300, cooling is not quite up to the standard of the Antec 900, but it’s still very good and a lot cheaper than the 900.
It’s whisper quiet too.
Read some more stuff here and there, concluded the Sileo is the best thing since sliced bread, cause I sez so, cause I wants it to be so
Seriously, basically it seems it comes with both the frontal and rear fans included in the package as default (initially, I had gotten the wrong idea it came with just the rear one and the other fan would have to be bought separately).
Thanks for the replies everyone (the Antec 300 would be a good option for me if not for the top ventilation grill - my PC is a great support for piling books ).