I work in the industry and on the face of it the cheap suites can look good but you really do pay your money and take your choice. Cheap toilets tend to have cheaper internals which are more likely to fail and they often have flimsy seats. Just watch out for poor finishes in the ceramic on cheaper ones however that doesn't tend to be a huge problem these days as most are made to a reasonable spec.
Baths are ok as long as you go with at least 5mm and it is installed properly according to the manufacturers instructions.
Shower trays and doors are an area I would recommend spending more money on if you are looking to cut the budget do it elsewhere- 6mm glass as a minimum on the door, look out for things like chrome cover caps, magnetic seals, and rollers that you can unclip for cleaning plus make sure it is backed by a decent guarantee, you might want to look out for a variant if easy-clean/glass shield etc. Shower trays -my preference is always either stone resin with an acrylic cap or a gel coat but not an acrylic tray- they age much quicker and tend to not look as good long term.
Brassware- you don't have to go for one of the big names but don't go for the cheapest of the cheap- they will scratch and if you get an issue it will end up being cheaper to buy a new tap than source the right washer! Nice taps can really make a difference to the overall finish of a bathroom.
Furniture- the cheaper stuff may not have as good a finish- you want to check the inside of units as well as the out, make sure there is nowhere for water to get in so it doesn't blow. Good quality soft close doors, tiny buffers on the base of a floorstanding unit so the carcase isn't sitting in spilled water. Generally the cheaper furniture is visibly so and you will see the difference.
I would recommend visiting an independent retailer near to you who has good local recommendations, these people know their stuff and don't want the hassle of you having problems later on.
I hope that helps! Good luck with your project.