was thinking about getting one of these but does it have any negative effects with balance etc?
There are some disadvantages, but it's down to personal preference
Coiled remote lines expand and retract the coils, this can 'tug' back when you hold the gun forward. It depends on where you mount your bottle and how long your reach is.
Straight remote lines have no coil and don't pull back. But instead they hang loose and wide
Any kind can catch on everything you pass, but straight ones are more likely to because they are always at full length
When using a remote you lose the 'stock' of a bottle in your shoulder, and if you use a curved base cylinder then by using a remote you lose the ergonomics of rotating it against your shoulder and being faster in aiming
If you use a remote, but then don't add a stock then you lose stability
It's harder to swap hands and then have a very tight remote line stretched across your chest
Balance will be affected, and though a remote line enables you to 'lighten' the gun, it's more important to be balanced
Disconnecting - a very basic old fashioned remote line cannot be removed whilst the air is on. So you are stuck to your gun or have to take off your vest, or have someone turn off your air, then degassing and disconnect
If it has a standard slide check valve then you can pop the valve which seals the line, then unclip and you can put down the gun. These can be prone to blowing o-rings, and will regularly blow o rings if the quality isn't too good and the o rings touch sharp edges
If it has a pro connect style then just squeeze a button to disconnect and it automatically seals. These are good, but the nipple is longer and could be damaged if you are not careful - e.g. Putting down a gun on concrete and hitting the asa male connector nipple
Filling - if your bottle is on your back you can't see the guage for how full it is, and cannot access the bottle to fill it. You need someone to help you fill (see one person crouched and leaning onto a fill station whilst a mate fills them) or you have to take off your kit to get to the bottle
Solve this by adding a remote fill line as well
There are two types of fill line - a heavy duty one which you permanently fit to your bottle to replace the nipple. This kind has an extra gauge so you can monitor pressure while filling
Or there is a clip on one which has the male and female fill nipple and socket