In my usual group two have gps, one has rangefinder, we like to know the distances. GPS systems do well to speed up play, a quick glance and you know the distance to center, quick club selection and you can be committed to the shot, rangefinder takes a little more time and you have to be able to see the pin, but if your hunting birdies its the ticket, my buddy's rangefinder has the slope feature and it works remarkably well, how it does it beats me but its great for elevated greens or long downhill par 3s.
I use the igolf unit, it requires no annual membership to work, so if you map your own courses on it, you have no additional charges, it'll hold more courses than most and had custom points and mark shot features. I bought mine used for $130, I see plenty more available for the same, the unit new is $229, they've came out this year with the igolf neo retail is $149 and it's getting good reviews, so they are becoming reasonable in price. This may surprise you but I care more to know the distance when its 55 yards than 255 yards, the 55 yarders I wanna get real close and the 255 yarders I'm just throwing the whole bag at it.

I'm sure you know MarkinTN1, that you can't use a rangefinder with a slope in tournament play.

I started using one last year and it has helped reduce my scores. You have to relearn your club distances (course markers are inconsistent) but it makes a difference. I play a lot of different courses that are new to me and it is a huge advantage there. It has a membership but you don't need to be a member to plot your own courses and use it.

I use a Skycaddie SG2 and I'm very happy with it... Yes, there is a yearly subscription for it - but it's only $29.99 for the level I chose and I get 10 course slots on the device as well as unlimited downloads of all mapped courses in Florida to swap in and out of the 10 spots. It's been more than worth it for me. The first few times I played I had issues with the signal being too weak and the yardage seemed to be off by 10 yds or so, but after a software update and learning how to reset the GPS signals - I am more than happy with the accuracy. I am not good enough to care about 2-3 yds differece though - maybe someone who is a scratch golfer might need more accurate yardages.

It is nice to be able to get front/middle/back yardages for greens, but I really like knowing how many yds I have to clear a hazard or reach the end of the fairway on a dogleg... The best feature for me is the yardage measure where you can mark where you hit a shot, drive/walk to the ball and then hit a button to see how far from your previous spot you are... Gives you a better idea of how far you hit a certain club off the tee or even on lay-up shots...

It has really helped me - especially on courses where the yardage markers/sprinklers are lacking...