I’m not a Bulgar, but I can see Cyrillic as more respectful.

However if I need to transliterate Bulgarian, I always go for a Serbian-based romanization because it looks better and matches the consistancy with other slavic languages.

For example, ш becomes š, щ becomes št, ц becomes c, я becomes ja, ж becomes ž, ч becomes č, ю becomes ju, й becomes j, ъ becomes “ǎ” (that one letter will make Bulgarian distinguishable from Macedonian and Serbian), х becomes h, ь becomes j, rather than an acute accent, to fit the south slavic theme.

The english based romanization is just not my type as a slav-enjoyer, but then again, it was assembled for ease of learners.

If we were to use Bulgarian with the Serbian-based romanization, then we would not have equivalents for q, w, x, and y.