Depends if you want a reciever that works correctly and all adveritised features working as advertised then yes swap to a DM800HD clone. If your not bothered and prepared to sit back and wait, while TM/DrLinux/UR TEAM/IQ Team/ITGate etc...continue to tell lies about when "fixes" will come out, or deny there are any issues...etc..then keep the TM800.
The benefits of a DM800HD would be:
1. All features work correctly, PVR recording, playback, timeshift to internal SATA or USB using any make/model of hard disk. Live streaming to PC, mobile phone etc...
2. Much more choice of images and plugins, any E2 plugin should work. Dedicated development teams working on images OpenPLI, EDG Nemesis, DreamElite, OOZoon, Gemini, NewNigma, PeterPan...etc etc.
3. Much larger user base, and much more support forums cater for DM stuff. Take a look around and see how many forums even talk about TM800...theres hardly any...
4. The price of a DM800HD from China is around 125 pounds delivered, theres no other E2 Linux reciever that comes close for price/performance/features ratio.
The Dm800HD clones have been around for a while now, and any problems have been ironed out, there were initial issues with HD glitches on older rev tuners...cured with the Rev M tuner.