I chose this e-collar because it has dedicated buttons for tone, buzz and stimulation. The transmitter has an excellent feel in my hand, great ergonomics. The display is large and bright even in direct sunlight. The 575 model is actually a 500 meter range not 500 yards which gives you more range than the Amazon sales write up states. I have a smooth collie with dense fur around his neck area so the longer prongs are a welcome addition. I originally tried the mini Educator brand and found their long prongs less effective due to being shorter than the SportDog brand. I really like the option of using tone/buzz or stim without having to adjust a setting on the go with this model. Even though my collie is 60 pounds with a dense neck coat he works well with the number two setting. The transmitter is also able to add an additional collar in the future. Build quality is very good and all buttons and switches feel sturdy and well put together.The only issue I had was with Amazon. I purchased my unit from Amazon Resale which used to be Amazon Warehouse deals. Amazon Resale are units that were previously purchased and returned then discount priced. The first unit shipped stated “Like New” but arrived without the transmitter. The second unit sent was also described as like new but arrived without a charger. Finally on the third attempt I received a perfectly satisfactory unit but without the factory box. Ironically the third unit without the box was the lowest priced unit and I saved a significant amount. These units are sold as new with full factory warranty not as refurbished units. I highly recommend SportDog but be careful buying from Amazon Resale, make sure all the items are supplied upon arrival.