The Shimano R540 is a great option if you don't want to spend a lot of money to get a dependable set of pedals. What you get are a practically indestructible set of pedals from the largest manufacturer in the business, and for not a lot of money!
The downside to these pedals is that they're a little heavier than other options, and sometimes they're sticky getting in and out of them. For the most part, especially if they'll be your first pedals, you will have made a solid choice going with this pedal from Shimano. You can dial in the amount of tension on the binding for a custom feel. You also get a proven, dependable pedal body and spindle that will last for years and/or thousands of miles.
Weighing in at 336g, these pedals aren't obese, but they aren't the lightest option, either. The ride with these pedals is very similar to the ride with other pedals--the difference is clipping in and out.
What you need to know about these pedals is basically this: they are the lowest budget option from Shimano, but they are built to last and will perform solidly for miles and miles.