not using a lot of fuel, money, etc
economical
clever, original, and inventive
ingenious /ɪnˈdʒiːnɪəs/
very modern and using the most recent ideas and methods
state of the art
unique
one-of-a-kind
weighing only a little or less than average
lightweight
working or operating quickly and effectively in an organized way
efficient
smooth, shiny, and lying close to the body, and therefore looking well cared for; not untidy and with no parts sticking out:
sleek
Someone or something that is reliable can be trusted or believed because he, she, or it works or behaves well in the way you expect
reliable
not breaking easily OR strong, healthy, full of flavour
robust /rə(ʊ)ˈbʌst/
able to last and be used for a long time without becoming damaged
durable
extremely beautiful or attractive
stunning
light and small enough to be easily carried or moved
portable
useful or convenient:
handy