I am a former Bryce user my self (Bryce 5.5) the thing with Terragen 2 and its node based approach to doing things is that you the artist have greater control over the look of your terrain than in Bryce. With that control, admittedly is a stepper learning curve, and thus slower progress but in the end you have a better result (With Time, Patience and Practice).
With Bryce with its presets which maybe more friendly to beginners (No place in production) you end up with canned results that can end up looking the same, that may have been OK in the 90's but not now.
The reason I stopped using Bryce in the first place was that I'd see all these great landscapes on Renderosity and they where done with Terragen Classic, which up until then I'd only toyed with; whilst waiting for internet files to download: then one day whilst over at Renderosity I decided to get real about using Terragen and with help form members of the community over at what is now
Terragen.org and then here on these forums thats what I did.
My first introduction to the world of digital landscapes was using an early demo version of Vista (Now Vista Pro) off the cover disk of Amiga Format Magazine which had a vary similar camera placement system to Terragen Classic: This was back in the Amiga 500 days.
Once you get use to Terragen you may not want to go back, and remember what Yoda said to Luke No, Try Not...Do or Do Not, There is no Try.
Regards to you.
Cyber-Angel