I have a Denon 100th Anniversary integrated amp. I'm considering to switch to a Bryston integrated, either the discontinued B100 or new B135, just the basic models with no DAC or phono. A review with specs of the Denon can be found here:
http://www.audioholics.com/amplifier-reviews/denon-pma-a100-integrated-amp-video
How do the Denon and Brystons compare? Certainly the 20 year warranty and Bryston customer service is a big plus for me. The Denon at 57 pounds weighs almost twice as much as the Brystons - does this "mean" anything, or are they using different amp technologies that lead to different weights? Are there any benefits or specs for the Brystons that stand out and should sway me to get a Bryston integrated? Thank you for any information or opinions. James feel free to comment, you're allowed to be as biased as you want 
Hi!
The choice would come down to the speakers used and personal preferences.
Both the Bryston and the Denon are class A/B amplifiers but they are vastily different from one another. The Bryston uses a bipolar power stage with (I think) 4 devices per channel while the Denon uses 'ultra high-current MOS' power stage with just 2 devices per channel. The Bryston uses lower overall gain which means lower noise at lower listening volumes but to keep things simple, both topologies have their advantages and disadvantages.
To put things in some context, the Denon is a very powerful amplifier (and yes, the weight plays a role here). Denon rates their amplifiers very conservatively, to put it mildly. While the A100 is rated at 80W (20-20k, 0.1% THD), it surpasses these numbers comfortably and delivers 125W continuous, and a lot more during dynamic peaks. However, the main thing about Denon's MOSFET stage is the current delivery. This means that the circuit basically delivers a proportionally linear ratio between power and impedance. In other words, it will deliver almost 250W into 4, 500W into 2 and almost a kiloWatt into a single Ohm load. The MOSFETs are rated at 160A each so this gives an idea about their thermal capacity. The A100 is a part of Denon's 'reference design' series and this is what these amplifiers are known for. The weight you've noted is derived from two hefty power transformers, two big reservoir caps and big heatsinks.
If your speakers are more difficult to drive, the Denon should be the preferred choice.
That being said, Bryston will likely sound slightly cleaner and possibly have a slightly lower noise floor. But it won't be very happy driving a low impedance and/or low sensitivity speaker in which case the benefits of a lower noise floor will become less important and the lack of dynamics more important.
Also, keep in mind that while Bryston does offer 20-year guarantee and their amplifiers are built to last, the A100, like other 'reference design' series, is made in Denon's 'Shirakawa Audio Works' which is probably the most advanced production facility of this type in the world. I have never heard someone managing to destroy an amplifier from this series so they too are known to last.
The Denon comes equipped with a superb MM/MC phono stage as standard, the Bryston comes with an MM but only as an option.
With Denon, you won't get the service support and the Denon CEO will most certainly not reply to your questions on Audio Circle like Mr. Tanner of Bryston does so generously.
So, both are really fantastic amplifiers but like I said in the beginning, it inevitably comes down to your speakers and preferences.
Also, note that the B100 and B135 use different preamplifier and power amplifier sections. The B100 is based on the BP16 pre and 2B pro, while the B135 is based on the BP17 pre and 2.5B pro. Additionally, there are two versions of the B135, the original I just mentioned also known as the 'SST2' (or 'squared' for short) and the new B135 'cubed' version which is similar to the SST2 but uses a newer input stage in the power amplifier circuit. Both use the identical preamplifier circuit to the best of my knowledge. I cannot say for certain how big the differences are between these three but the differences in price are significant. If I didn't have the money for a B135 'cubed', I'd opt for the B100 because I prefer it's analog volume pot to the resistor ladder one in the B135 SST2.
Hope this helps mate,
Cheers - Antun
