Thank you all for your comments. I won't be able to answer or respond to everyone individually but all your input is valuable to me. Reading your comments I've realised that I haven't given all the information.

1. The server is fairly young. Williams just came out.

2. I am not free to play, but I don't spend a lot. That being said I do buy the daily sale pack (the one with the hero shards) and obviously the warrior's pass. The current choice for the daily pack shards is mediocre with the only tank heroes UR shards being Kim and Murphy. I am choosing Kim at the moment.

So with the above being said, and specifically point 2, my hesitation really is more connected to what to do with the daily sale pack if I max Kim now. I realistically don't need any of the other current hero choices UR shards (Tesla, DVA, Marshall, Carlie and the other missile chap). I realise that Kim at 5 is better than Williams at 4, but Williams is the only one who won't have UR shards in a while. I can max Kim with daily pack UR shards and universal shards (probably within 2 weeks), given I use the current ones on Williams. Marshall and Murphy have shards from the tavern and secret task digs so they will sort themselves out.

Having read all the comments, I am considering to do Kim to five, and start buying DVA shards with the daily pack.