I have LEDs for all of my turn signals, from superbrightleds.com. I have resistors wired in for the front and rear ones (not necessary for thet side ones). At night the brightness is fine because the LED clusters I got all have outward facing LEDs as well as some radially mounted LEDs so the lighting is much more even. During the day I think the rear LEDs light aren't as bright as what I had, before I just had a clear incandescent bulb that was way too bright though.
During the day the sidemarker isn't really bright enough to be seen, it just looks like a little dot of light. It is a five LED model with one large LED facing outward and four LEDs mounted perpendicular for more even lighting.
Oh and for colors, I have amber front, amber side (the amber doesn't match perfectly though), and red rear.