I am looking for some good long lasting 3rd party batteries for the XF300, are there any reputable brands or types worth getting please that you recommend?

I use 4 of this ones:
http://www.staldi.net/ebay/images/4072_1.jpg
http://www.staldi.net/ebay/images/4072_3.jpg

Lithium Ionen Akku Li-BP970 7,4V 7200 mAh

But u have to charge them with the older loader from the XH-Series.

Before i had some cheaper and they all give up around 1 year...
They was rests of jusing them with my older XH-A1 and XH-A1s

I am currently using 3 Wasabi Power batteries, they are absolutely awesome. Can be charged with Canon charger and camcorder. I am using the XF100.

Highly recommended, and super cheap. The LCD battery bar is accurate, however, the minutes left on battery function won't show. But it is no a problem at all because battery bar is there.

Amazon.com: Wasabi Power Battery for Canon BP-970G and Canon GL1, GL2, XF100, XF105, XF300, XF305, XH-A1, XH-G1, XL H1, XL H1A, XL H1S, XL1, XL1, XL1S, XL2: Camera & Photo

Just ordered an Wasabi batt.