This is a very large bungalow and almost immaculate. There's lots good about it, including a DVD player that the owners oddly didn't connect up, an almost total lack of traffic noise and a butcher, local shop, bar and newsagent with a sideline in bread within 150-250 metres. The buses are cheap and impressive, though they thin out a lot around lunchtime. The locality almost feels more like a large village or small town. You won't need me to tell you that you can get Eurostar through-ticketed via TGV to Biarritz to get there. If you want to chill out, read a few books, wander down to the seaside when the mood takes you, then this place may be close to ideal.
The most obvious issue some people will have with it is how far it is from the main part of the town and the seafront - around 15 minutes walk. It doesn't sound a lot, but it is moderately downhill (i.e. uphill on the way back), and it's far enough that over a week or so it could be a niggle especially if you have mobility problems. There are restaurants, but not huge numbers of them and not particularly close (perhaps ten minutes). Though there is a nice patio for any warm sunny weather that you have, there's no view of the sea, no sound of the waves from the front door, no log burner to huddle round. Those things can be very nice, some places do have them, and if they're more important to you than impressive spaciousness, then this may not be the right place for you, particularly if you struggle to walk long distances. There are places (not necessarily at Biarritz) that are close to stations where you can get trains up and down the coast to all sorts of other places, and if that's what you're after, I'm afraid this isn't it. I'm not saying don't go there, just be aware of what it is and what it's not.
It's also worth mentioning that there is a €500 damage deposit, payable in cash on arrival, and that's a lot of banknotes, though if you make frequent trips to Europe it may not bother you.