I'm not going to go over old ground again, but as you say, it's unreliable, noisy (mains hum like an electric motorized wasp on speed) and in my opinion has an eyesore of a keypad. I had a hell of a time with them many many years ago and as with all "fingers burned" episodes that was me and the veritas finished.
Try making extensive use of the search facility so kindly provided by Dave and all will become clear as to why i'm set in my opinion. Scantronic kit is good, the reason I recomended the premier was the easy to follow instructions. A Proper engineer would know how to wire a tamper loop or a powered detector to a panel so wouldn't need the same type of instructions as provided with the texecom stuff.
I've already made my recomondation BTW, for DIY fit a premier. any electrical wholesaler or market stall (I kid you not, the local market has them for sale) will supply you one and most of the accessories are also available and the price is cheap, you can buy a complete premier system with all the accessories FITTED for less money than you could buy a galaxy panel on it's own for.
Most people will have absolutely no use for most of the advanced functions the galaxy provides though so from a functionality point of view there is no difference in them buying a premier or a galaxy,
Myself, I have an all singing and dancing galaxy 504 installed. but there again, I'm a professional alarm engineer so know how to both wire and program it to make best use of it's facilities and functions.
Regards
Bellman