I guess, for sample based instruments, it can compete sound wise…there is no reason why it should not. I would say, a big deal is the source (the samples) which are used for the instrument.
(I use a lot of orchestra libraries so…) I guess for rompler, if you mean emulating older rompler keyboads I don’t see why not. For realistic instruments these days, it depends on the instrument. For a bare minimum realistic violin or brass instrument you need round robins, crossfades between dynamic layers during playback of a note (pp, ff etc) and then script transitions between samples to play back legatos. You also might have crossfades between playback of vibrato and non vibrato. All of that ideally with multiple mic positions. And if you want to be able to use instruments that complex without killing all of your RAM on one instrument–you need disk streaming/buffering features (well, even then it uses a lot of RAM )
Renoise on the other hand is great as a sampler when I am focusing on a smaller and particular set of sounds to work with because it’s just so fast and has a ton of features that I don’t get elsewhere… plus it is so much more cpu efficient than the competition for some particular tasks.
Speaking of samples and Renoise: one lifesaving feature is the export instrument to samples option–this is amazing for building sample libraries out my modular synthesis patches