I've been playing Bass for a very long time and in that time have used many amps. Back in the 80's I owned my first Mesa amp (Bass 400+). That amp changed the my perception on amps for good. As has been mentioned above, they are a cut above any other company out there when it comes to the care they put into their products; starting with design all the way through customer service. You simply cannot do better than them in this industry. With that said, Mesa consistently puts out quality products that in many ways outpaces their competition...consistently. Think back, have you ever heard of them producing anything that is considered a "dog" by any standard?
I've been using a Subway D-800 since they were announced a few years back. It is an outstanding amp that I have absolute confidence in for any application. It's the last part of my rig that I worry about. Here's an interesting fact, I run the D-800 to push a ~30 year old Mesa 4x10 and it just simply rocks! that's right, the cabinet is ~30 years old, that right there should speak volumes to you. In fact, I also play on the worship team at my church and use a D-800 Preamp DI.
Now with that said, let me address tone and ease of use. The interface to the D-800 is absolutely idot proof meaning I can get a workable sound from it without much effort at all. In fact, I've not found a setting that makes me sit back and say "that sounds awful". The amp just gets out of your way and delivers every time! Forget about all the talk about this "nice to have" and that.
Yeah, you are going to have to pay some cash to get that kind of reliability and commitment to quality. Let's say you bought an amp that is half the price, ask yourself will that really satisfy you? Is the price point the only deciding factor? If the answer to the latter question is "yes" then go ahead and buy the cheaper unit. I can almost guarantee you'll be back looking for something else in the short-term. I played that game for years. the old statement "you get what you pay for" could never be more true in this case IMHO.
If this is not enough, ask yourself this; why do people continue to pay premium dollars for Mesa equipment? How could they have survived this long in a market where I can get stuff made overseas, with less quality, and charge an inflated price for it? I think the answer is simple; Mesa consistently delivers quality and players have come to realize that and trust the brand to deliver every time.
Here's a true story from back when I owned the Bass 400+. Shortly after buying the amp, I had a question about it and the dealer suggested I call Mesa support. So, I did and spoke to a CSR who took the model and serial number and asked if I could hang on a minute. Very quickly someone took me off hold and introduced themselves as the person who worked on my specific amp and spoke with me for quite a while about it, enthusiastically answering any questions that came up. In all my years dealing with companies, I've NEVER had that kind of customer service. That experience made me a life long customer. And that policy for customer care has not changed to this day!
I know, I sound like a huge "fanboy". The truth is, winning my loyalty as a consumer is not easy, I've got very high standards especially where music gear is concerned. I don't like to part with hard earned cash any more than the next guy. So, I like to make sure what I spend my money on is going to give me a return on my investment. If they were awful, I would be singing a completely different tune. In short, get the Mesa, you won't be sorry.