As a concept, he works better than Boo, as the idea of a combination of the Z-Senshi and their foes as the ultimate threat seems fitting as a potential endgame opponent (and infinitely better executed than the Evil Dragons were as that concept). In terms of overall execution, he does feel to be a missed opportunity in many ways, as it would've been nice to see Cell have existential pondering given his origin to add more depth, even if it were as basic as Anime Mewtwo. Shame Toriyama's writing style is too simplistic for him to add much psychological themes to the plot.
Putting that aside and focusing on Cell compared to Freeza and Boo, he's better than the latter, given Boo's regeneration and absorption made him just feel like Cell 2.0 outside of Fat Boo's development. Whilst Cell's personality being influenced by others is a unique feature that could offer him greater complexity than other DB characters if given better writing, his overall execution makes it seem derivative in comparison to Freeza. His schtik of being the Z-Senshi's power used against them wasn't given enough thematic prominance to offer him the same link to the cast as Freeza did with Vegeta and Goku either.
To summarise, Freeza > Cell > Boo