The biggest difference between mushrooms and LSD is the duration of the experience (LSD usually a good 12 hours mushrooms about 8). Lots of different mushrooms that seem to effect people differently so it's hard it's hard to generalize about what kind of experience "mushrooms" will give you. Five people take the same hallucinogens and all five will have a different experience, so the trip is a bit less dependent on the drug as it is on the person. Dosage has a big effect on the experience as well. Most people will advise you to start slow your first time and if it doesn't seem to be working DON'T take more because these things take time and you can really overdo it. I'd suggest not doubling up on what ever suggested dosage you have been told to take but I wouldn't necessarily say that you need to avoid have an intense experience your first time.

I've seen way more "bad trips" on acid but I'm not so sure that it's acids fault. If you have a bad trip it's way easier to get through it in 8 hours than 12. Most people I know prefer one or the other and mostly they prefer mushrooms. I'd also say that a bad trip isn't a function of a particular drug as much as it is the mind set you have going into it.

THE MOST IMPORTANT PART OF A FIRST TRIP - Go into it with a positive attitude! Your first trip is an introduction into a part of your senses, mind, and emotions that you probably haven't fully experienced before, it's an exhilarating adventure. If you are scared of yourself than be ready for a difficult time, you'll probably learn about why you scare yourself if you are open to the experience. No matter what that shits on a timer and every thing will be OK in the end. If you are excited to get to know more about your senses and self than you should be psyched at the journey you are about to take. I suggest getting yourself excited at the fun and novel time you are about to have or getting yourself centered and mellow, prepared to take a contemplative journey into your inner being.

You are still you while you are tripping. Inexperienced people can sometimes feel a little lost at sea or panicky. If they are with a sober or experienced person it's usually easy to help them realize that all is well and that there is nothing to worry about. You can call upon all the wisdom and good sense you had when you were sober when you are tripping. If you need to ground yourself just take a minute and do a little inventory on who you are, what you know and realize that everything is fine and you are just passing through a bit of your own self.

Make sure you are hydrated. Nature is great, dance parties can be good, physical activities like walking, playing in shallow water listening to or playing music are all good ways to keep things moving and discover new aspects of the effects these wild chemicals have on your brain.