As an expat living in Singapore who has visited Bintan about 10 times, I have to say that I found the Banyu Biru Villas at Nirwana Gardens "OK". There were pluses and minuses.

On the plus side:

1) I took a lot of my own food and was able to save quite a lot of money not dining in the restaurants every day. The villa has a kitchen, microwave, rice cooker and water boiler (bring your own t bags though!)
2) The food and beverage was OK, quite good in some areas. The breakfast buffet (included) was quite good and ticked all the boxes. The hotel has to spread itself a bit thin to cater for western, Chinese, Korean and Japanese guests on it's menu. We did try some of the Western food, which usually falls short if you are mainly catering to Asian guests e.g. Pizza (which was just smothered in cheese) and so stuck to the Asian food, which was very good. Great Satay!
3) Whilst the Nirwana pool was always full and had no sunbed space, we are the Banyu Villas had the whole pool to ourselves all day, everyday. We saw 2 other people all holiday.
4) The service at the hotel is good and the staff all speak good English and are friendly. We had a few issues including needing extra amenities, lost an item, late check out and all our queries were dealt with very quickly, professionally and positively. Good service!

On the downside:

1) The villa we stayed in was, well shoddy! It was very clean, but very basic and run down. During our time there were about 5 others villas in occupancy of about 30+ villas. Some of them are renovated very nicely (we peeked). You'd think that if they are not being used, you would put your guests in the nice villas to entice them back and tell their friends eh? Apparently not! Our villa was short on towels, toilet paper, toiletries, the bed lined was distgusting. We had to ask for our bedlinen to be changed as my child had an accident one night. I removed the sheets and was ASTONISHED to see an awful multi-stained mattress with no cover (in a kids room!) and pillows that had numerous orange stains on them. It was terrible. Also stained cushions on the sofa, 3 frying pans but no pan (although brought one very quickly when asked), no drainer or tea towel. The worst though was the bathroom, or should I say lack of bathroom. I was looking forward to having a nice relaxing bath in my "villa". I was quite astonished to see that, not only was there no bath, but there was no shower either. A shower in the corner of a bathroom with a shower curtain pulled around it, is not a proper bathroom. That is, probably the worst bathroom I have ever seen in Asia. Also, a vanity mirror over the toilet! No shelves to put things on. My toiletries were laid on the floor in the shower and were on the bathroom floor as I had nowhere to put them.

2) The pool at the Villas only opens at 10am on a weekday? So we have paid for a villa and the pool doesn't open till 10am? Firstly let me tell you that Bintan is a 50 minute ferry from Singapore and usually a short stay for most people. It is one hour behind. That means we get up really early as our time clock is still on Singapore time. Also it means that Bintan is blazing hot at 0800 and the sun starts to go down at 1630-1700. At 0700 the breakfast buffet is packed, people are round the pool by 0800. So why O why is the pool open at 1000? We did, after all, pay for our villa, so the pool should be open at 0800. We did however, just go to the pool, ignore the red chains and signs saying it was closed and turn the slide water on ourselves! Which brings me to my next point about the pool:

3) This is the only hotel in the world I have ever stayed in where they make you sign a huge form saying that is you do not bring your towels back the same day by 17.30pm, they will charge you 25 Singapore dollars each towel. Firstly, the towels are not worth 25 Sing each, they are cheap and nasty and secondly I find the fact that the management think I am going to steal their towels quite insulting. Perhaps if the management gave the guests at the villas more than 1 towel between 2 guests, then they may not walk off with them.

A bit of a scathing review above, however we did have a good time and I think the staff at the hotel are very good. Staying in any hotel in Bintan is not cheap and I do think that the hotel is short changing it's guests a bit. Would I stay there again - probably not!