What are the range's dimensions?

It is a 30-inch freestanding range, the standard width for most US kitchen cutouts. Check the depth and height against your space before ordering.

Does it have a griddle?

Yes. The range includes a griddle along with a grill, both usable on the gas cooktop.

Is the oven gas or electric?

The oven is gas, and the cooktop burners are gas too. It needs a gas line connection, not a 240V outlet.

How does it compare with a convection gas range?

It has a plain gas oven without a convection fan, so browning and heat distribution are less even than convection models. Convection ranges offer more features.

The range, griddle and grill come with it. Gas connector lines and installation parts are usually sold separately.

Is the Hotpoint RGBS300DM worth it?

It is a fair buy for a simple 30-inch gas range with a griddle and grill. It lacks convection and self-clean, so compare it with those models if even baking matters to you.