Laptop presentation technology is moving forward very rapidly. Anything LESS than 1000 lumens and XGA high resolution of 1024 x 768 or higher is going to be unsatisfactory compared to 16mm on a Mark 300. Digital offers some strong advantages such as digital quality sound and a short throw distance of around 30' to cover the 30' wide screen. Simplicity of operation is truly plug and play. If you go digital watch for screen hot spots, or fall off and distortion around the edges.
Different manufacturers offer very different quality.
We use Epson and In-Focus . We've used Peavey 110 DSL speakers most of our history. These are good midrange units with acceptable bass, good midrange and high level tweeters come wrapped in heavy box construction making them pretty indestructible. Naturally, you don't have to buy new. Most music equipment rental outfits can supply all these things by the night, complete with tripods and audio cable for a fraction of the total cost.