I purchased a shimano compatible 10 speed cassette made by IRD ( www.interlocracing.com ) that was an 11-34.
Full retail price was rediculous but the LBS gave it to me for 1/2 price.

Other factors than gearing contribute to how a bike feels. I achieved a huge benefit recently by changing MTB tires to road tires. Bike fit, handlebars and geometry also come in to play.