What bike to look for

like rossco said everyone will give you different advice and a lot depends on the exact type of riding you are currently doing and what you want to progress into.

For me when I'm looking for a new bike the first thing I always do is set myself a price limit I will not go above. You can always spend more money on a bike and some of the sales guys will try and up sell you above what you are comfortable with.

Then I would have a set of features I want (amount of suspension, wheel size, tubeless wheels, etc) and features that would be good (2x10 gearing stuff like that) if I can get them for the price.

Then I would look around online at the different brands to see what they offer around my price. The bigger brands Giant, Trek and Specialised will generally have better value for money in regards to components and in my opinion that all make pretty good bikes, while more boutique brands have more unique features. Then once you have a short list see which ones you can demo and if there are any sales/specials on. If you can wait till around Aug the are generally sales on as the new year models come out. (I saved $900 on a $4500 bike).

Not sure what sort of bikes you have now but it sounds like you are both sort of starting out/reasonable new to mountain biking and. I think 120-130mm dual suspension can handle most stuff that the average rider wants to do. Seriously think about a dropper seat post as they make a huge amount of difference to your ability to move around on the bike on tricky sections, increasing your safety and confidence immensely. Also think about tubeless or at least convertible to tubeless as it aother feature that I think makes a huge performance difference and basically eliminates flats.

That's a pretty good call, unless they're a big-W special you can learn a lot on a hard tail. It would be easy to spend a lot of money on a fancy dually and then realise it's not the right category or even sport for you.

IIRC correctly the intermediate trail at OMV is still a fair jump up from the green trail, maybe some time on a more open trail like Terry Hills would be a good intermediate step to help build your familiarity and confidence

I just upgraded

I was in the same situation as you but I had an old giant rincon 98 model so pretty much an antique compared with today's bikes.
I bought a giant anthem x2 2010 model on here for $880 and it's amazing. Your welcome to try it if you want? I'm on manly dam most Sundays. I found having rear suspension a bit strange at first as it felt like I had a flat tyre! Well worth holing out for a bargain though I was happy with the oldie but it did start to hold me back in confidence.

forget wheel size and all the rest of the marketing BS. Try and get a test ride on a few different bikes and buy the only that feels the best to you that is in your budget (or more realistically out of your budget but has some martketing BS to help you justify your overspend.)

It really is that simple.

make friends with fellow riders and ask for a quick spin on theirs

Failing that a few shops, bike companys organise test ride days on the trails which is the best.

failing that the quick car park test ride of the floor stock will give you a relative guide.

Go with the one you like.

Have fun.

Buy another bike.

repeat