Go to ATH with low expectations & you may come out with a positive feel about your stay. The Hotels & the catering offer have both gone way downhill over the years. You'll get a better nights sleep in a Premier Inn & the Premier Inn breakfast puts the Towers breakfast offering to shame. A Premier Inn will cost a lot less than ATH too.
You'd be better saving up & heading to Europa Park - they show what CAN be done if the powers-that-be want it to happen. Their hotels are amazing, the food & drink offering is amazing, the theme park is amazing too. Spot the common word... not often you'd see the word amazing in an Alton Towers trip report.
The difference is the management at Europa Park care - it's a family owned business & guest experience matters to them a lot. I've been in Hotel Colosseo having an evening meal and Roland Mack was wandering around, inspecting / sampling the buffet, talking to guests etc. Would you see Mr Varney taking that level of interest in the Alton Towers Hotel? Err, no. I bet the ATH have to get a special food order in if he stays there, i.e. no "sawdust special" sausages at breakfast.