Aren’t you making any profit or why do you want to switch? I mean you are happy with the proxies you use right now and they work great, better just keep them up.
According to this list the best proxies for twitter are Smartproxy, Geosurf and BlazingSEO. AFAIK, the last one is also the cheapest option, but doesn’t fare as good in other categories.
So depending on your needs and budget, you can see what fits you best.
I suggest going for the provider that would have big pool of IPs since that is important if you want to make more accounts and work on automatic tools. Smartproxy would be a good choice, since their prices are affordable and you can use all the pool of proxies for your work. You can also check Stormproxies of geosurf since they also offer IG proxies which isn’t so common in the market.