Personally, I use only the open style, I feel they "point" faster in competition. (I don't like looking through a tube). What ever you decide to use MAKE sure it will be bright enough in the sunlight. (I live in Arizona) My 1st.choice has always been C-More Railways.They have different size modules available from 3min. to 16 min. If your wants/needs change. Depending on the gun, rifle, pistol, revolver I use the small 3mm. dots on rifles, 5/6 mm on handguns. Factory service is very good, just about any issue can be addressed if needed. I have no problem buying used and they generally run about $150.00. You can buy elevated picatinny mounts if you wish a higher mount..... That said, I do use the mini dots were it;s not practical to use a larger style red dot. There are some with lifetime warranties. The choice is yours. I forgot to add, there are Chinese copies of the C-Mores, a real one will have the serial # hand engraved on the unit.