A chargecooler is much smaller and generally lighter and reduces the lag you often get when putting a large intercooler in place. However, they're more complicated and rely on water being pumped around to work.
An intercooler is a just a big radiator, which is way cheaper to impliment and never goes wrong. The bigger you go the more lag will be introduced... so choose wisely. A too smaller intercooler with have heatsoak on long full throttle runs. You can buy cheap generic intercoolers off ebay which will do the job just fine, although will have to make the pipework and elbow bits up yourself.
I would personally go for an intercooler solution... the last thing you want is more complexity under the hood... maybe you can retro-fit the megane one to reduce costs?
Rich