翻訳 - 日本語-英語 - 素晴らしいです

desu is something like is, so it would be better as ´It is wonderful/magnificent.´

Actually, the ending "desu" here just indicates the formal level of politeness.
The informal (friendly) form of "it is wonderful" would be
Subarashii
and the very very formal would be
Subarashuu gozaimasu
---Ian ^_^