A Second Cell Phone Connection dilema

So, I resurrected my beloved HTC, literally from the dead when I managed to get my Hands on a Brand new Battery for it. Now, Its just lying without a sim cars, so, I want to buy a second Sim card for my E71 and put my Vodafone Sim back into my HTC.

Cant decide on What to buy. Should I go for a Docomo. I have heard nightmares about the connectivity etc.