Is MGM signature a good place to stay for 21st birthday?

The accommodations are more like an apartment than a hotel room which is nice. Compared to places like the Cosmo or or Flamingo, it's a longer walk to the strip. And it's a pretty good walk to the MGM casino, pool, dining, clubs. But it's still a lot easier to get places than from Mandalay Bay. 

If you're looking for good prices right on the strip, Treasure Island's rooms are a good value for the money. The on-campus dining, shows, etc are kind of mediocre but there are plenty of other choices all around. 

you can get much better prices on Fremont Street, downtown Las Vegas.

no. terrible.       

I've stayed at the MGM signature.  The rooms are over the top nice.  The bathrooms are huge.  The furnishings are super nice.  They have a kitchenette. 

I've also stayed at the MGM Grand, whose rooms are more than sufficient for the average person.

Downside of the MGM Signature - it's a freaking hike, albeit inside, to go from the Signature to the Grand.  It would be quicker to take a taxi, but getting a taxi at the Signature could be a long process.

Consider that the average person is in their room only to sleep.

My suggestion, if you're going to be in LV from Sunday to Thursday, stay at the Luxor.  You could get 4 or 5 rooms for $250/night there.  There is a free monorail from the Luxor to the Excalibur (across the street from MGM Grand).

LV is expensive on Friday and Saturday nights.  The balance of the week the hotels are begging for people to fill the over 150K hotel rooms in the city.

It's a perfectly good choice, but if that $250 is for one night, that's pricey for Las Vegas. I just got an offer for the MGM near me for $79 a night for a double room. Unless you're going during a poker tournament, you ought to be able to do better than that. They probably charge more because they're like condos. The entire Strip is walkable, and there's a sky car. But the MGM is down at the far end. If you want to be more central, to have access to all the casinos, restaurants, and bars, look at some other choices. 

It's about a 5-minute walk from Signature to MGM Grand.  If you look at a map you can see that it's not on the strip like MGM Grand is.  I believe they are connected by a walkway, but they aren't exactly attached.

Signature doesn't have a casino and has limited hotel amenities.  You have access to the MGM Grand amenities, but again that's a bit of a walk.  There isn't really much of anything to do in the Signature resort itself.

The Signature isn't really a 21st birthday destination.  It has really nice rooms and the location is okay, but it wouldn't be my first choice for any trip - especially a 21st birthday.  That price seems quite high too.  You should be able to find much cheaper rooms at a more convenient hotel.

Be aware that many things in Vegas are still closed.  Any open clubs are operating as lounges with required reservations and limited capacity.  Bars and restaurants that are open are limited as well. 

The signature was going to be residences that didn’t sell, so that is why they are bigger, but there are no hotel amenities in the buildings and no casino. It’s quieter.  It’s a pretty big slep to the MGM itself and the strip if that isn’t an issue for you.  The MGM is at one far end of the strip as well, not central.  Do research on what will and will not be open. The residences are nice overall but not really a hotel/casino atmosphere

You haven't mentioned when your birthday is.  However, since you are booking rooms, it must be fairly soon.

- Vegas does have some bars / clubs open but they are transformed to lounges not nightclubs

- Many of the restaurants are still closed.

Does the $250 include all the fees and taxes?

Everything in Vegas looks close but it's all far.  But it's behind the MGM so you are officially off the strip.

MGM is near the beginning of the strip not the heart.  But you are across from T-Mobile arena.