Friends overall is the better show from my point of view for a few reasons:
- overall better/more interesting characters
Mother has Barney Stinson.. i give them that and he's hilarious and often enough carries the episode/show by himself but the others share good scenes.. one episode it's Marshal who's awesome, the next one it's Lily etc.
I feel Friends had the more well rounded cast and no breakout character who carried the show
- Mother has dug itself too deep by dragging out the main storyline
Mother was.. well, about Ted's journey to find the Mother. For the first few seasons it was fun to see little tidbits revealed (i even dug Ted and Robin even when they spoiled the fact that she can't be the mother in the pilot episode!) and some glimpses but by season 4 or 5 i became fed up with it. It's season 8 now and they've even put the whole Mother storyline besides to drag out Barney's and Robin's relationship/supposed wedding
So overall Friends wins for me.. not because it has better writing or better actors but because Mother made too many bad choices to take away the spot from Friends (whose quality dropped a bit after season 3/4 but still remained on a good level).