I'd say go with the most comfortable, the ones that will make you want to go and do the hard sessions.
Whilst for race shoes you want the fastest and may be prepared to put up with a bit of discomfort, for training shoes, then yes you want something that feels fast and not a clumpy heavy shoe, but does it really matter if it's the fastest ? Does it matter if your reps are 3 seconds slower ? As long as you put the same effort in, the physiological benefit will be the same, and at the end of the day, it's how we perform in races that matters, not how we perform in training.
So, buy the shoe that will allow you to train at your hardest, and don't worry too much about whether it's the "fastest"
I got this,...