You have two by products in the market. First, is the aluminium, if you have tight pocket and willing to spend in between 20k to 25k then choose aluminium, it is lighter than the high tensitle steel, whereas if you need lighter, reliable and stronger frame nothing withstand the chromoly it is the best in the market. Chromoly 4130 is the technology most used in bmx and many other categories of biking making your ride light, strong choose wisely.
All the bike comes with 20 inch frame size where you can choose the right bike for you they have 20.5 inches model and 20.75 inches, nawdays they are coming up with 21 to 21.5 inches bmx frames where the difference nothing but it entirely depends what you are looking up to so try taking a test ride if you need bigger frame.
Purpose of your ride
Be very clear about what you want, do you want to do jumps, flatland tricks or for racing. Once you know your ride you are good to go there are different category where you may find different models with different purpose accordingly build up.
Dont expect parts last forever. Once you get your new bike doesn’t mean it will never get damaged or you never need to replace any parts for quiet good long time which is not true. You need to change parts or entire bike a times specially if you do street or dirt jumps.
Exclude swampy ride
Look for sealed bearing, bike with no sealed bearing means no stable riding and will face more whobbling issue on more frequent basis. Always look for sealed hub, bottom bracket, sealed headsets will allow bike to move smoother with less of hassle.
Look before you spend know about good and low quality parts. Cheap parts may cost you a lot but there are chances may end up buying a bike which rip apart in no time hence living you with disappointed. If your bike came with parts named as odyssey, animal, kink, subrosa, snafu and sunday than be rest assured, something good is on your way.
It is not all about just building the bike these days weight really matters well not asking you to spend a lot to get super light bike, find out frame, parts are intermediate light enough so it does not consume enough energy to do tricks or on race track.