I started this thread, and I have been using Xtumble bot for a few weeks now. I am just now really getting to play with it....my day job has been running me ragged.
The software is legit. Does everything it says it will, and it does it all excellent for the most part. Account creation can be a little frustrating, but that's not really the bot's fault. Tumblr is hellbent on kicking spammers out and you will not have a 100% success rate on account creation. But, let's be honest. If you are considering building hundred's to thousands of accounts bannings are going to happen.
With regard to proxies, I still haven't found a good solution to this part of the equation. However, using proxies from buyproxies.org has been working well for me. I'm even using hotmail accounts....had a few hundred left over. (Hotmail accounts are NOT recommended by the way) but they still work for me. I have a few accounts that were made with public proxies and using a hotmail address and they are still alive and kicking....for now....I do not expect these accounts to be around long haha.
Regardless, this software is legit. It is expensive to use (ie proxies) but I am more than satisfied with it so far. Seriously though, if you can't/won't spend money for 50ish proxies to get started, then I am not sure how much use this software will be for you. I am currently have around 60 proxies ready to be used (my project for this week) and I am sure I will make a healthy ROI when all is said and done.
To each his own, but if you are looking at botting this social network, this is a tool you need to own.
It's a pro's tool with a pro's cost, but it delivers pro results.
Sorry if this is a rambling message, I just got home from a 13 hour shift so I am a little brain dead haha.