Formal:
* আপনারা চমৎকার (apnara chomotkar) - This is the most formal way to say "you are great" and is used when addressing someone older or of higher status.
Informal:
* তুমি সুন্দর (tumi sundor) - This literally means "you are beautiful" but can be used to express that someone is great in general.
* তুমি ভালো (tumi valo) - This means "you are good" and is a more general way to say "you are great".
* তুমি দারুন (tumi darun) - This means "you are awesome" and is a more informal and casual way to say "you are great".
For a specific skill or quality:
* তুমি খুব ভালো [skill] (tumi khub valo [skill]) - This means "you are very good at [skill]" - for example, "তুমি খুব ভালো গান গাইতে পারো" (tumi khub valo gan gaite paro) - "You are very good at singing."
You can also use the phrase "খুব ভালো" (khub valo) which means "very good" to express that something is great. For example, "এই খাবার খুব ভালো" (ei khabar khub valo) - "This food is very good".
Remember to choose the appropriate phrase based on the context and your relationship with the person you're talking to.