Every guitar player has an opinion on effect pedals and whether "true bypass" or "buffered" pedals provide the most accurate tone. Here are a couple of resources that may dispel some of the myths. but be assured, whichever type you use, we have choices from Boss, Dunlop, Fishman, MXR, Electro-Harmonix, T.C Electronic, DigiTech, Vox and Line 6.
Article by legendary effect pedal guru Pete Cornish. And here's a short video with an actual demonstration. Enjoy!