I use Illustrator to do my lettering and word balloons. CSP does have lettering/balloon capabilities, but they're currently not the best- the kerning functions are horrible and it doesnt do well with fonts that have ligatures.
Also Illustrator allows me to create balloons like this:
As for my fonts- I get most of them from Comicraft & Blambot. Comicraft has some SUPERB fonts, but they are pretty expensive UNLESS you catch them on New Year's Day when they have a sale on all of their fonts for the price of the new year(i.e., in 2020, fonts will be on sale for $20.20 each all day on Jan 1). Blambot has great fonts as well- his is cheaper(I can buy his fonts any day of the year coz they usually average about $20-$25); he also has FREE fonts that he allows small indie and webcomic artists to use.