I keep seeing people recommending those massive Titan, Erbauer or noname monsters, and I struggle to understand just why. Certainly they are cheap, and they are powerful, but they are also SO heavy. I can understand that if you need to do a lot of demolition or breaking out at or near ground level then they are a really cheap alternative to a full size breaker or SDS Max hammer drill/breaker, but for ordinary drilling tasks they are simply too heavy and too bulky to use, especially if you intend to use them above waist height, and their weight means they aren't much use for other tasks either, such as wall tile stripping floor to ceiling, full wall height chasing, notching-out timbers, electrical back box sinking or mortar raking (you can get SDS tooling to do all that and more). For most drilling and light chiselling work a 2 to 3kg (the so-called "2kg class") SDS drill is far less tiring to use, especially for extended periods as well as being more accurate, but either way I can endorse the recommendation to choose a model with rotation stop (chiselling mode) because it is so handy to have that.
Before making their choice I urge the OP to consider exactly the type of work they envisage doing, and if it isn't at least 50% heavy breaking, to go for a lightweight tool. At one time these were expensive, but looking this afternoon there a few 2kg SDS drills in the £50 to £60 range which boast an impact strength of 2J (joules) or above - and you ideally need 2J or more for a drill to be usefully fast and be able to undertake chiselling work
A last note about SDS drill bits - in trade use 90% of the holes I drill will be for brown plugs (7mm) or red plugs (5.5mm), so a couple of different length bits in those sizes will generally suffice. If you need any other sizes, e.g. 10mm for injection DPC work, 14mm or 16mm for resin anchors, etc it's best to just buy as and when needed. They are readily available at SFX/TS and many oter places, but note that a good quality bit, such as a Heller TriJet drills a lot faster and will last a lot longer than a cheap Silverline one in the same size