It really comes down to your personal taste in decorating. Some people prefer the look of the decora switches, some could care less. Same can be said for the decora receptacles and the 'screwless' cover plates. I have seen many that have the decora switches, but standard receptacles. 'Screwless' cover plates are definitely more expensive than standard ones. But, it really is up to you to decide "is it worth it?" After all, you are going to be the one who looks at it and uses it every day. I can promise that whichever one you choose, it will look really good from my house.
I'll agree with Lediy99 that $14 extra per switch seems awfully steep. Although I do find them a little more time-consuming to install (they can be a little more of a pain to plumb/level, especially in a multi-gang box). Are you sure that they were just quoting the switches and not decora receptacles too?
If you are handy, you could certainly make the change later as a DIY job, as suggested by Lediy99.